Question 1

Java command-line arguments indexing: determine what prints and whether an exception occurs.  public class CommandArgs {  public static void main(String[] args) {  String s1 = args[1];  String s2 = args[2];  String s3 = args[3];  String s4 = args[4]…

Accepted Answer

Introduction / Context: This program highlights array bounds and evaluation order in Java. Even though the final print references s2, the statements assigning s1…s4 execute sequentially first. If any assignment throws an exception, the print is never reached. Given Data / Assumptions: args supplied: {"1", "2", "3", "4"}. Valid indices: 0..3 for four elements. Code attempts to access args[4]. Concept / Approach: Accessing args[4] with only four elements triggers ArrayIndexOutOfBoundsException. This happens before the System.out.print call, so nothing is printed successfully. Step-by-Step Solution: s1 = args[1] → "2" (valid).s2 = args[2] → "3" (valid).s3 = args[3] → "4" (valid).s4 = args[4] → throws ArrayIndexOutOfBoundsException.Program aborts; print statement is not executed. Verification / Alternative check: Removing the s4 line or guarding with if (args.length > 4) would allow the print “ args[2] = 3”. Why Other Options Are Wrong: args[2] = 2 / 3 / null: Would require reaching the print; the exception prevents it. Empty output: While nothing is printed, the precise reason is a runtime exception, which is the correct diagnostic choice. Common Pitfalls: Forgetting that args is zero-based; assuming later statements are skipped even when earlier ones fail. Final Answer: An exception is thrown at runtime.

Question 2

Java (jagged 3D int array) — how many lines will be printed by the nested loops?  public class Test  {  public static void main(String [] args)   {  int[][][] x = new int[3][][];  int i, j;  x[0] = new int[4][];  x[1] = new int[2][];  x[2] = new int…

Accepted Answer

Introduction / Context: This question checks your understanding of ragged (jagged) multidimensional arrays in Java and how many times a nested loop executes when each “row” has a different length. Specifically, you must total how many inner elements are created and printed as the code initializes subarrays for a 3D-like jagged structure and prints their lengths. Given Data / Assumptions: x is declared as int[][][] with the first dimension sized to 3. x[0] has length 4, x[1] has length 2, and x[2] has length 5. For each i and j, the code assigns x[i][j] = new int[i + j + 1] and immediately prints one line via System.out.println. No exceptions are thrown; the code compiles and runs. Concept / Approach: The println call happens once per j iteration of the inner loop. Therefore, the total number of printed lines equals the sum of the lengths of x[i] for i = 0..2. The actual sizes of the innermost arrays (i + j + 1) influence the printed numbers but do not affect the count of lines printed, only their content. Step-by-Step Solution: Compute the number of inner-loop iterations for each i.For i = 0: x[0].length = 4 → 4 prints.For i = 1: x[1].length = 2 → 2 prints.For i = 2: x[2].length = 5 → 5 prints.Sum total prints = 4 + 2 + 5 = 11. Verification / Alternative check: Manually list the j values per i (0..3 for i=0, 0..1 for i=1, 0..4 for i=2). Counting each println confirms 11 total lines. Changing the formula i + j + 1 would change the lengths printed but not the number of lines. Why Other Options Are Wrong: 7, 9, 13: These are incorrect sums of the row lengths. Compilation fails: The code uses standard Java jagged arrays; it compiles. Common Pitfalls: Confusing the number of lines printed with the values printed; the numeric content (lengths) varies, but the count depends only on how many j iterations occur. Final Answer: 11

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