Question 1

JSP execution model basics At runtime, a JavaServer Page (JSP) is first transformed by the container into which executable server-side artifact?

Accepted Answer

Introduction / Context: JSP (JavaServer Pages) provides a templating model where HTML (or other markup) is interleaved with server-side Java elements. Understanding the lifecycle clarifies deployment, performance, and debugging behavior in Java web applications. Given Data / Assumptions: A JSP is deployed to a Java EE/Servlet container (for example, Tomcat). The container manages compilation and execution. No browser plugins (like applets) are involved in server execution. Concept / Approach: When a JSP is requested, the container translates the JSP into a Java source file that extends the servlet base classes. It then compiles this source into bytecode and loads it as a servlet. Subsequent requests run the compiled servlet class until the JSP is changed, at which point the container recompiles as needed. Thus, at runtime a JSP becomes a servlet, not an applet. Step-by-Step Solution: JSP received → translate to Java servlet source.Compile source to servlet bytecode (a .class).Load and execute the servlet to generate dynamic content.On JSP updates, retranslate/recompile automatically. Verification / Alternative check: Servlet container documentation describes JSP translation-phases and servlet lifecycle; IDE tools can show the generated servlet code for debugging. Why Other Options Are Wrong: A: Applets run in a browser JVM; JSPs run on the server. C/D/E: Do not reflect the standard JSP compilation model. Common Pitfalls: Assuming JSPs execute as scripts; they execute as compiled servlets. Editing generated servlet code—changes are overwritten; edit the JSP itself. Final Answer: Java servlet.

Question 2

JDBC driver categories and networking: In Java Database Connectivity (JDBC), which driver Types are designed for use over communications networks (for example, connecting over TCP/IP to middleware or directly to a database server)? Select the most a…

Accepted Answer

Introduction / Context: JDBC drivers are classified into four historical types based on how they translate JDBC calls to database-specific protocols. Understanding which types are intended for networked use helps developers pick drivers that work well in distributed applications, servlet containers, and microservices. Given Data / Assumptions: The four classic JDBC types are Type 1, Type 2, Type 3, and Type 4. We are concerned with drivers designed for communication over a network. Typical production deployments use TCP/IP between application and database servers. Concept / Approach: Type 3 (network protocol driver) is a pure-Java driver that sends JDBC calls to a middleware server using a database-independent protocol; the middleware then translates to the database protocol. Type 4 (thin driver) is also pure Java and speaks the database’s native protocol directly to the database over the network. Both are built for networked environments and are common in app servers like Tomcat, JBoss, and Spring Boot deployments. Step-by-Step Solution: Identify driver types and transport behavior: Type 3 uses middleware over the network; Type 4 uses the DB’s native protocol over the network.Contrast with Type 1 (JDBC-ODBC bridge) and Type 2 (native API partly): these typically rely on local libraries or ODBC and are not ideal for pure network deployments.Conclude that both Type 3 and Type 4 are designed for network usage. Verification / Alternative check: Vendor documentation for widely used drivers (for example, PostgreSQL’s Type 4 driver, MySQL Connector/J) confirms direct TCP/IP connectivity without native libraries. Historical Type 3 products relied on middleware hubs reachable over the network. Why Other Options Are Wrong: Type 3 only / Type 4 only: incomplete; both are intended for networked operation. Neither: contradicts the core purpose of Types 3 and 4. Common Pitfalls: Confusing Type numbers with performance guarantees; real-world performance depends on driver quality and database protocol, not just the Type. Also, Type 1 is obsolete and should not be used in production. Final Answer: Both Type 3 and Type 4

Question 3

JDBC driver taxonomy: According to Sun/Oracle’s classic classification, how many JDBC driver Types are defined (Type 1 through Type N)?

Accepted Answer

Introduction / Context: JDBC drivers historically have been grouped into “Types” that describe how a driver translates JDBC API calls into database-specific operations. Knowing the number and nature of these Types helps clarify compatibility and deployment implications for Java applications. Given Data / Assumptions: The classification originates from Sun Microsystems and persists in documentation. Types are numbered sequentially and commonly referenced in interviews and textbooks. We are asked for the count of Types in the classic scheme. Concept / Approach: There are four classic Types: Type 1 (JDBC-ODBC bridge), Type 2 (native-API partly Java driver), Type 3 (network protocol driver using middleware), and Type 4 (thin driver using native database protocol over the network). Modern practice overwhelmingly favors Type 4 drivers for portability and simple deployment. Step-by-Step Solution: Recall the enumerated list of Types (1 through 4).Map each Type to its brief definition for validation.Confirm the total is four and select that option. Verification / Alternative check: Check any mainstream JDBC driver documentation; the Type is often stated (for example, PostgreSQL and MySQL drivers are Type 4). Why Other Options Are Wrong: One/Two/Three: omit one or more established Types and do not reflect the historical taxonomy. Common Pitfalls: Assuming the Type determines feature completeness; real capability depends on the specific driver implementation and database. Final Answer: Four

Question 4

MySQL surrogate keys: Which column property is used in MySQL to generate surrogate key values automatically for each inserted row (monotonic integers without manual assignment)?

Accepted Answer

Introduction / Context: Surrogate keys are system-generated identifiers that do not carry business meaning. In MySQL, a popular way to implement them is by using a special column attribute that auto-generates a new number for each inserted row, avoiding manual key management and race conditions. Given Data / Assumptions: You are designing a primary key with no inherent business semantics. MySQL is the database platform. You prefer a built-in mechanism rather than triggers. Concept / Approach: The AUTO_INCREMENT attribute on an integer column instructs MySQL to assign the next available numeric value automatically when a row is inserted (unless explicitly provided). It is commonly combined with PRIMARY KEY. While sequences are used in some other DBMS products, classic MySQL (prior to introducing sequence objects in later versions) uses AUTO_INCREMENT for this behavior across storage engines like InnoDB. Step-by-Step Solution: Define the column as INT (or BIGINT) with AUTO_INCREMENT.Designate it as PRIMARY KEY to ensure uniqueness and indexing.Insert rows without supplying the key; MySQL assigns values automatically. Verification / Alternative check: Run INSERT statements and observe that LAST_INSERT_ID() reflects the generated key, confirming correct AUTO_INCREMENT behavior. Why Other Options Are Wrong: UNIQUE: enforces uniqueness but does not generate values. SEQUENCE: not the classic MySQL mechanism (used in other DBMSs). “Not implemented”: incorrect—AUTO_INCREMENT is standard in MySQL. Common Pitfalls: Resetting AUTO_INCREMENT without understanding gaps; assuming sequential values are guaranteed without gaps after deletes or rollbacks. Final Answer: AUTO_INCREMENT

Question 5

JavaBeans basics: Which of the following statements correctly describe a standard JavaBean used in enterprise Java (intended for property introspection and tool support)? Choose the best answer.

Accepted Answer

Introduction / Context: The JavaBeans pattern defines conventions that enable frameworks, IDEs, and libraries to discover properties via reflection and to serialize/deserialize objects in a predictable way. Recognizing these conventions is fundamental in JSP/Servlet, Spring, and many Java UI toolkits. Given Data / Assumptions: A “JavaBean” here refers to the classic beans specification (not necessarily EJBs). Beans expose properties through accessor (getter) and mutator (setter) methods. Tooling often expects a public no-argument constructor for instantiation. Concept / Approach: Core JavaBeans conventions include private fields, public getters and setters, and a public no-arg constructor. While a bean must provide a no-arg constructor, it can also define additional overloaded constructors when appropriate. Exposing public instance variables breaks encapsulation and undermines property introspection, so beans rely on methods like getName/setName rather than public fields. Therefore, statements A, B, and C together reflect JavaBeans practice, making “All of the above” correct in this context. Step-by-Step Solution: Confirm that beans should not use public instance fields → true.Confirm property access via get/set methods → true.Note allowance for multiple constructors provided a no-arg constructor exists → true.Therefore, all statements hold → choose “All of the above”. Verification / Alternative check: Check typical bean classes in frameworks: they include a no-arg constructor, private fields, and get/set pairs; many also provide convenience constructors for initialization. Why Other Options Are Wrong: Each individual statement is correct but incomplete by itself; only the combined “All of the above” reflects the complete view expected of JavaBeans. Common Pitfalls: Confusing JavaBeans with Enterprise JavaBeans (EJBs); exposing public fields and breaking encapsulation; forgetting the mandatory no-arg constructor required by many tools. Final Answer: All of the above are true of a Java bean.

Question 6

JDBC-ODBC bridge identification: Which JDBC driver Type corresponds to the historical JDBC-ODBC bridge (now obsolete and removed from modern JDKs)?

Accepted Answer

Introduction / Context: The JDBC-ODBC bridge was an early solution for connecting Java applications to databases through the ODBC layer. Although it simplified initial adoption, it imposed native dependencies and has been deprecated and removed in modern Java distributions. Given Data / Assumptions: We are mapping the bridge to a JDBC Type number. Type 1 drivers rely on ODBC and native libraries. Type 4 drivers are the modern, pure-Java norm. Concept / Approach: Type 1 is explicitly defined as the JDBC-ODBC bridge. It translates JDBC calls to ODBC calls, which are then handled by the ODBC driver for the target database. This approach requires native DLLs/so files and is not suitable for portable, containerized deployments. Step-by-Step Solution: Recall the four Types and their definitions.Identify the one that uses ODBC: Type 1.Select Type 1 as the correct answer. Verification / Alternative check: Review JDK documentation: the JDBC-ODBC bridge (sun.jdbc.odbc.JdbcOdbcDriver) was removed after Java 8 and is clearly described as Type 1. Why Other Options Are Wrong: Type 2 uses native DB APIs but not ODBC specifically. Type 3 and Type 4 are pure Java network drivers. Common Pitfalls: Attempting to use the bridge in modern JDKs; mixing up Type 2 (native API) with the ODBC bridge. Final Answer: Type 1

Question 7

MySQL system metadata location: In which built-in MySQL database are system tables and metadata (for example, user accounts and privileges) stored by default?

Accepted Answer

Introduction / Context: MySQL ships with several internal schemas used for administration and instrumentation. Knowing where metadata lives helps DBAs perform tasks such as privilege management, server configuration, and diagnostics using SQL queries. Given Data / Assumptions: You are using standard MySQL server distributions. System tables for users, privileges, and other core metadata exist. We must identify the canonical schema name that contains these objects. Concept / Approach: The built-in schema named mysql stores core system tables (for example, user, db, tables_priv in historical versions). Additional schemas like information_schema and performance_schema provide metadata views and performance instrumentation, but privilege and configuration tables historically reside in the mysql database itself, which is the answer closest to the options provided. Step-by-Step Solution: List built-in schemas: mysql, information_schema, performance_schema, sys (helper views).Identify where core system tables are: mysql schema.Choose “In the MySQL database mysql”. Verification / Alternative check: Run SHOW DATABASES; and DESCRIBE mysql.user; on a MySQL instance to verify the presence of system tables in the mysql schema. Why Other Options Are Wrong: “metadata” and “metasql” are not standard built-in schema names. “None of the above” is incorrect because mysql is the correct built-in schema. Common Pitfalls: Confusing information_schema (read-only views of metadata) with the underlying mysql system tables; assuming system tables are absent in managed cloud offerings (they may be restricted but still exist). Final Answer: In the MySQL database mysql

Question 8

Java servlet container history: Which servlet processor (container) was jointly developed by the Apache Software Foundation with significant collaboration from Sun, and is widely used to host servlets and JSPs?

Accepted Answer

Introduction / Context: To run servlets and JavaServer Pages (JSPs), you need a compliant servlet container. Historically, Apache and Sun collaborated to provide a reference implementation that evolved into a production-grade, open-source project widely adopted across the industry. Given Data / Assumptions: The question refers to a servlet processor/container used for servlets and JSP. Apache and Sun collaborated early on a reference implementation. We must choose the product name matching that effort. Concept / Approach: Apache Tomcat is an open-source servlet container developed by the Apache Software Foundation, with significant early contributions from Sun Microsystems. Tomcat implements the Jakarta Servlet and JSP specifications, providing HTTP handling, servlet lifecycle management, and JSP compilation to servlets. Step-by-Step Solution: Identify the product category: servlet/JSP container.Match collaborative history: Apache + Sun contributions → Tomcat.Select Apache Tomcat as the correct answer. Verification / Alternative check: Documentation and historical notes show Tomcat’s lineage as a reference/production implementation tied to the servlet/JSP specs, unlike the generic Apache HTTP Server (a web server, not a servlet container by itself). Why Other Options Are Wrong: Apache Web server: serves HTTP but is not a servlet container without modules/bridges. Sun servlet processor: not the common product name; Tomcat is the recognized container. None of the above: incorrect because Tomcat fits precisely. Common Pitfalls: Confusing a general web server with a servlet container; assuming any web server can execute servlets directly without a Java container. Final Answer: Apache Tomcat

Question 9

Running compiled Java programs: To execute a compiled Java application (class files), what must be installed and running on the machine at runtime?

Accepted Answer

Introduction / Context: Java compiles source code (.java) into platform-neutral bytecode (.class). This bytecode is executed by a runtime environment that provides memory management, class loading, and just-in-time compilation, enabling “write once, run anywhere.” Given Data / Assumptions: We are discussing execution of already compiled class files. A runtime is necessary to interpret or JIT-compile bytecode. We are not building or compiling code at runtime. Concept / Approach: The Java Virtual Machine (JVM) is the runtime that loads class files, verifies bytecode safety, manages memory (heap/stack/GC), and executes the program. The Java compiler (javac) is needed at build time, not runtime. Bytecode is the artifact, not a program you “run” directly without the JVM. A web browser is optional and relevant only for legacy applets (now deprecated). Step-by-Step Solution: Compile source → produce bytecode class/jar files.Install a JRE/JDK that includes the JVM.Launch with the JVM (java command) which executes the bytecode. Verification / Alternative check: Attempt to run a class file without a JVM; the OS cannot execute it natively. With the JVM installed, the java MainClass command runs successfully. Why Other Options Are Wrong: Java compiler: for compilation, not execution. Java bytecode: is the program representation, not an executable environment. Web browser: unrelated except for obsolete applet technology. Common Pitfalls: Confusing JRE (runtime only) with JDK (runtime + compiler/tools); assuming native execution without a JVM. Final Answer: Java virtual machine

Question 10

Open-source DBMS identification: ________ is a well-known open-source relational DBMS product that runs on UNIX, Linux, and Windows platforms and is frequently used with web applications.

Accepted Answer

Introduction / Context: Open-source relational database management systems power a large percentage of modern web and enterprise applications. Being able to recognize widely deployed products and their typical environments is basic knowledge for developers and DBAs alike. Given Data / Assumptions: The product runs across major operating systems: UNIX, Linux, Windows. It is open source and widely adopted. It is a DBMS, not a programming API or web technology. Concept / Approach: MySQL is an open-source RDBMS known for LAMP/LEMP stacks (Linux/UNIX, Apache/Nginx, MySQL, PHP/Python). It supports SQL, replication, and storage engines like InnoDB. Alternative well-known open-source DBMSs include PostgreSQL, but among the options provided, MySQL is the correct match. The other options are not DBMS products. Step-by-Step Solution: Filter options for “DBMS product” versus “technology/API”.Identify MySQL as the only DBMS listed.Confirm cross-platform support: UNIX, Linux, Windows → MySQL qualifies. Verification / Alternative check: Check typical stacks: WordPress, MediaWiki, and many applications support MySQL as a first-class database. Why Other Options Are Wrong: JSP/SQL and JDBC/SQL: these are programming acronyms/APIs, not DBMS products. Sun ACCESS: not a recognized open-source DBMS; likely a distractor. Common Pitfalls: Confusing query languages (SQL) or APIs (JDBC) with database servers; overlooking that multiple open-source DBMSs exist but only one appears in the choices. Final Answer: MySQL

Question 11

JSP execution model in Tomcat: How does Apache Tomcat execute a JSP (JavaServer Page) request in its servlet container architecture?

Accepted Answer

Introduction / Context: JSP is a server-side view technology that compiles to a servlet. In servlet containers like Apache Tomcat, requests are handled within a multithreaded Java process. Understanding this execution model helps with performance tuning, thread safety, and resource management. Given Data / Assumptions: Tomcat is a Java servlet/JSP container. JSPs are compiled into servlets automatically on first use or deployment. Threads are used to handle multiple simultaneous requests inside the same JVM. Concept / Approach: Tomcat translates a JSP into Java source for a servlet, compiles it to bytecode, loads it, and executes it within the container. Each incoming request is processed by a thread from Tomcat’s thread pool calling the servlet’s service method. This is not CGI (external process per request) nor an independent OS process per JSP; it is a method invocation within the JVM managed by Tomcat’s threading model. Step-by-Step Solution: JSP → translated to servlet source.Servlet source → compiled to class and loaded into the JVM.Requests → dispatched to the servlet by Tomcat threads from a pool. Verification / Alternative check: Observe Tomcat work directories where generated servlet code is stored; thread dumps show request-handling threads executing servlet methods, confirming the thread-based model. Why Other Options Are Wrong: CGI: spawns external processes, not used by Tomcat for JSPs. Independent process: Tomcat does not spawn a process per JSP request. None of the above: incorrect because threads are the correct mechanism. Common Pitfalls: Writing non-thread-safe JSP/servlet code (for example, mutable static fields); assuming per-request isolation like CGI when in fact state can be shared within the JVM process. Final Answer: By one of Tomcat's threads

Question 12

Java History — Who Created the Java Programming Language? In the context of software history, identify the organization credited with inventing the Java programming language.

Accepted Answer

Introduction: Knowing who created Java helps place the language in its historical and technological context. Java has influenced web development, enterprise systems, and mobile platforms for decades, so recognizing its origin is essential for students of programming and software engineering. Given Data / Assumptions: The question asks for the inventor organization behind Java. Options list well-known software companies and groups. We must choose the single best answer that matches historical fact. Concept / Approach: Java was initiated in the early 1990s as a project originally called Oak. It emerged from Sun Microsystems and was led by a team including James Gosling, often called the “father of Java.” The language and its virtual machine were publicly released in the mid-1990s and quickly became central to server-side and enterprise development. Step-by-Step Solution: 1) Recall that James Gosling and colleagues at Sun Microsystems started the project.2) Recognize that Netscape popularized Java applets in browsers but did not invent Java.3) Understand that Microsoft created competing technologies (for example, J++ historically, later .NET/C#), not Java.4) Conclude that “Sun” (Sun Microsystems) is the correct creator. Verification / Alternative check: Standard references in programming history consistently attribute Java’s creation to Sun Microsystems, with James Gosling prominently cited as the language’s principal designer. Why Other Options Are Wrong: Netscape: Helped distribute Java via browsers, but did not invent it. Microsoft: Built competing tools and runtimes, not Java itself. None of the above: Incorrect because Sun is listed. Apache Software Foundation: Oversees many Java ecosystem projects, but did not invent the language. Common Pitfalls: Confusing the company that popularized Java on the web (Netscape) with the company that actually created the language (Sun Microsystems). Final Answer: Sun

Question 13

JDBC Driver Types — Suitable for Both Applets and Servlets Which JDBC driver type(s) are appropriate for use in either Java applet code running on a client machine or Java servlet code running on a web server?

Accepted Answer

Introduction: JDBC drivers come in different architectures, each with implications for deployment in browsers (applets) and servers (servlets). Understanding which types are pure Java and do not require native libraries or local ODBC layers is vital for portability and security in both environments. Given Data / Assumptions: Applets historically ran in client browsers with restricted access and no native libraries. Servlets run on the server and can use any driver, but portability is preferred. Type 3 and Type 4 drivers are pure Java and do not rely on local native code. Concept / Approach: Type 3 (network protocol) drivers communicate via a middleware server, and Type 4 (thin) drivers talk directly to the DBMS using the database’s wire protocol. Both are written in Java and avoid native dependencies, making them suitable for both applet and servlet contexts. Type 1 relies on ODBC; Type 2 uses native APIs, both unsuitable for applet security sandboxes and less portable in general. Step-by-Step Solution: 1) Eliminate Type 1 (requires client-side ODBC) and Type 2 (requires native libraries).2) Confirm Type 3 is pure Java with middleware; Type 4 is pure Java with direct protocol.3) Conclude that both Type 3 and Type 4 fit applet and servlet usage. Verification / Alternative check: Vendor documentation and Java textbooks traditionally recommend Type 3 or Type 4 for browser and server environments due to their portability and ease of deployment. Why Other Options Are Wrong: Type 1/2 combinations: Depend on client-side ODBC or native code, problematic for applets. Type 4 only: Type 4 works, but so does Type 3; excluding it is unnecessary. Common Pitfalls: Forgetting that applet sandboxes prohibit native libraries, ruling out Types 1 and 2. Final Answer: Both Type 3 and Type 4

Question 14

Acronym Expansion — What Does JDBC Stand For? Choose the correct expansion of the acronym JDBC as used in Java data access.

Accepted Answer

Introduction: JDBC is the foundational API for database access in Java. Understanding the expansion of the acronym reinforces its purpose and the architectural role it plays in enterprise applications and services. Given Data / Assumptions: The question asks for the official meaning of JDBC. JDBC is used across Java SE, EE, and popular frameworks. The correct phrase emphasizes connectivity, not components or control. Concept / Approach: JDBC stands for Java Database Connectivity. It provides interfaces and classes to connect to relational databases, execute SQL statements, and process results. It is analogous in spirit to ODBC, but designed for Java with type mappings and driver-based architecture. Step-by-Step Solution: 1) Recognize that JDBC is an API focused on connectivity between Java and databases.2) Eliminate expansions that substitute “components” or “control,” which are not official.3) Select “Java Database Connectivity.” Verification / Alternative check: Official Java documentation and textbooks uniformly define JDBC as Java Database Connectivity. Why Other Options Are Wrong: Components/Control/Data Binding Connector: Not standard expansions and misrepresent JDBC’s function. None of the above: Incorrect as the right expansion is present. Common Pitfalls: Associating JDBC with ORM tools; ORM frameworks often use JDBC under the hood but are conceptually separate. Final Answer: Java Database Connectivity

Question 15

Client-Side Execution — What Is Downloaded via HTTP and Runs on the User’s Computer? Identify the Java technology that is sent to the user over HTTP, launched using the HTTP protocol by the user’s environment, and executed on the user’s computer wit…

Accepted Answer

Introduction: Before modern client-side frameworks became dominant, small Java programs called applets were embedded in web pages and executed on the user’s machine via a browser plugin or the Java Plug-in. This question distinguishes applets from server-side components such as servlets. Given Data / Assumptions: Delivery occurs over HTTP to the client. Execution occurs on the user’s machine within a JVM-enabled environment. We must choose among common Java components. Concept / Approach: Applets are client-side Java programs downloaded to the browser and executed locally. Servlets, in contrast, run on the server under a servlet container (for example, Tomcat). A generic “Java application” is not specifically delivered and launched via the browser; it typically runs as a standalone program. Therefore, the description clearly matches a Java applet. Step-by-Step Solution: 1) Identify where the code runs (client vs. server).2) Map client-side downloaded execution to the “applet” concept.3) Exclude server-side servlet execution.4) Select “A Java applet.” Verification / Alternative check: Historic Java web tutorials describe the applet lifecycle (init, start, stop, destroy) and the need for a browser plug-in or appletviewer, affirming client-side execution after HTTP delivery. Why Other Options Are Wrong: Java application: Not necessarily delivered via HTTP for in-browser execution. Java servlet: Runs on the server, not the user’s computer. JSF page: A server-side view technology rendered to HTML; execution is server-side. Common Pitfalls: Conflating where code runs; applets (client) vs. servlets/JSF (server). Final Answer: A Java applet

Question 16

JSP Lifecycle — Number of In-Memory Instances How many copies (instances) of a given JSP page's generated servlet are typically kept in memory by the servlet container at one time under normal configuration?

Accepted Answer

Introduction: JavaServer Pages (JSP) are compiled into servlets. Understanding the default instance model helps developers reason about concurrency, thread safety, and the correct use of instance variables versus request-scoped data. Given Data / Assumptions: A JSP is translated into a servlet class by the container. By default, a single servlet instance handles many requests concurrently using multiple threads. Containers may create additional instances under special configurations, but that is not the default. Concept / Approach: The conventional servlet/JSP model is “one instance, many threads.” The container maintains one instance of the generated servlet and dispatches concurrent requests to it using separate threads. Therefore, developers must avoid storing per-request state in instance fields unless properly synchronized or avoided altogether. Step-by-Step Solution: 1) Recall that JSPs become servlets managed by the container.2) Recognize the default singleton-like instance model for servlets/JSPs.3) Conclude that typically one instance is in memory for a given JSP. Verification / Alternative check: Servlet specifications describe concurrent handling via multiple threads per servlet instance, with SingleThreadModel deprecated long ago, reinforcing the one-instance default assumption. Why Other Options Are Wrong: Two/Three/Unlimited: Not the default instance policy; scaling is via threads, not many instances. One per active session: Incorrect; sessions do not create separate servlet instances. Common Pitfalls: Using servlet/JSP instance fields for request data and causing race conditions in concurrent access. Final Answer: One

Question 17

Java Compilation Output — What Is Bytecode? Choose the description that best defines Java bytecode produced by the Java compiler.

Accepted Answer

Introduction: Java compiles source files into an intermediate representation called bytecode, stored in .class files. Understanding bytecode is essential for appreciating Java’s “write once, run anywhere” promise via the Java Virtual Machine (JVM). Given Data / Assumptions: Java source is compiled by javac into .class files. The JVM interprets or JIT-compiles bytecode to machine instructions at runtime. Bytecode is designed to be portable across platforms. Concept / Approach: Bytecode is not source code (Java code) nor is it machine-specific native code. It is a standardized, platform-neutral instruction set executed by the JVM. This indirection enables the same .class files (or packaged .jar) to run on different operating systems and CPU architectures that have compatible JVM implementations. Step-by-Step Solution: 1) Eliminate “Java code” because bytecode is the compiled form, not the source.2) Eliminate “machine-specific code” and “native libraries” because portability is bytecode’s goal.3) Select “machine-independent code.” Verification / Alternative check: The JVM specification defines the bytecode instruction set and class file format, confirming its platform neutrality prior to runtime JIT compilation. Why Other Options Are Wrong: Machine-specific / Native: Describe platform-dependent binaries, not bytecode. Java code: Refers to .java source files, not compiled .class files. None of the above: Incorrect because a correct choice is provided. Common Pitfalls: Assuming bytecode runs directly on hardware; it runs on the JVM, which may JIT-compile it to native code at runtime. Final Answer: Machine-independent code

Question 18

Server-Side Execution — What Handles HTTP Requests on the Web Server? Which Java component is invoked on the web server via HTTP to process requests coming from a user’s browser?

Accepted Answer

Introduction: On the server side of web applications, Java servlets are the core components that receive HTTP requests and generate HTTP responses. Recognizing the difference between client-side and server-side Java technologies is fundamental to web architecture in Java. Given Data / Assumptions: Requests originate from a user’s web browser. Processing occurs on the web server. We must choose a server-side handler. Concept / Approach: Servlets run within a servlet container (such as Tomcat or Jetty). They implement methods like doGet and doPost, interact with request/response objects, and produce dynamic content. Applets are downloaded to and run on the client; standalone Java applications are not inherently invoked by HTTP on the server. Therefore, the correct server-side component is the servlet. Step-by-Step Solution: 1) Determine execution location: server, not client.2) Identify canonical Java HTTP handler on the server: servlet.3) Exclude applets and generic applications as they are not the HTTP endpoints on the server. Verification / Alternative check: Servlet specifications define the lifecycle and mapping of servlets to URL patterns, confirming their role as HTTP request processors on the server. Why Other Options Are Wrong: Applet: Client-side component. Java application: Not necessarily an HTTP endpoint. JNLP app: Client-side launch technology. Common Pitfalls: Confusing download-and-run client technologies with server-side request handlers. Final Answer: A Java servlet

Question 19

JSP Scripting Languages — What Does JSP Support? Identify which programming or scripting languages are supported directly within JavaServer Pages (JSP) for writing embedded code.

Accepted Answer

Introduction: JSP lets developers embed code fragments and expressions into HTML templates that are compiled into servlets. Knowing which language JSP natively supports avoids confusion with other server-side frameworks and ensures compatibility with the Java EE ecosystem. Given Data / Assumptions: Standard JSP relies on Java as the scripting language. VBScript and JScript are Microsoft scripting languages, not part of JSP. Other languages can be integrated through alternative engines, but not as native JSP scriptlets. Concept / Approach: JSP is part of the Java platform; embedded scriptlets, declarations, and expressions use Java syntax. Tag libraries and Expression Language (EL) provide higher-level abstractions, but when scriptlets appear, they are Java. Therefore, among the options provided, only “Java” is correct. Step-by-Step Solution: 1) Confirm that JSP compiles to a Java servlet.2) Recognize that code inside JSP scriptlets uses Java.3) Exclude VBScript and JScript as non-Java technologies.4) Select “Java only.” Verification / Alternative check: JSP specifications and examples show Java code in <% ... %> blocks, and the resulting .java servlet source generated by the container uses Java exclusively. Why Other Options Are Wrong: VBScript/JScript: Technologies for other platforms, not JSP. All of the above: Incorrect because JSP does not natively support those languages. Python via native scriptlets: Not supported by standard JSP. Common Pitfalls: Confusing JSP with general server-side templating engines that may embed various languages; JSP is Java-centric. Final Answer: Java only

Question 20

JDBC in Three-Tier Setups — Driver Types to Use In a three-tier architecture, and assuming the web server and DBMS run on the same machine, which JDBC driver type(s) are generally suitable choices?

Accepted Answer

Introduction: Choosing the right JDBC driver in a multi-tier architecture affects portability, performance, and operational simplicity. Pure Java drivers avoid native dependencies and are easier to deploy, especially across clustered or containerized environments. Given Data / Assumptions: The architecture is three-tier (browser, web/app server, database). The web server and DBMS may be co-located, but portability is still valuable. Type 3 and Type 4 are pure Java and widely recommended. Concept / Approach: Type 3 drivers use a middleware server; Type 4 drivers speak the DB wire protocol directly. Both run without native code, which simplifies deployment and scaling. Type 1 (JDBC-ODBC bridge) is obsolete and requires ODBC. Type 2 requires native libraries and complicates deployment and maintenance. Thus, Type 3 and Type 4 are the typical best choices in three-tier setups, regardless of server co-location with the DBMS. Step-by-Step Solution: 1) Prefer pure Java drivers for portability and ease of deployment.2) Discard Type 1 (legacy/ODBC) and Type 2 (native code).3) Select “Both Type 3 and Type 4.” Verification / Alternative check: Modern vendor guidance and practice overwhelmingly favor Type 4 in particular; Type 3 is also acceptable where middleware fits the architecture. Why Other Options Are Wrong: Type 1 only: Obsolete and unsuitable for production. Type 2 only: Ties you to native libraries; avoid when possible. All types: Overbroad; some types are undesirable. Type 1 and Type 4 only: Still includes the deprecated Type 1. Common Pitfalls: Underestimating deployment friction from native dependencies in scaled-out environments. Final Answer: Both Type 3 and Type 4

JDBC, Java Server Pages, and MySQL Questions