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  1. JDK
  2. JDK-4419723

Line number information for try-catch statement is not sufficient

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    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 1.3.1
    • Fix Version/s: 1.3.1_03
    • Component/s: tools
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      03
    • CPU:
      sparc
    • OS:
      solaris_8

      Backports

        Description

        Line number information generated for a try-catch statement is not
        sufficient for debugger to show more reasonable single-stepping information.

             1 import java.io.*;
             2
             3 public class HelloWorld {
             4 public static void main(String[] args) {
             5 int i = 10;
             6 System.out.println("Hello World!");
             7 try {
             8 if ((i % 2) == 0) {
             9 System.out.println("i = " + i + " is an even number.");
            10 Integer.parseInt("200");
            11 } else {
            12 System.out.println("i = " + i + " is an odd number.");
            13 Thread.sleep(10);
            14 }
            15 } catch (Exception e) {
            16 System.out.println("Exception caught!");
            17 }
            18
            19 System.out.println("Bye");
            20 }
            21 }
        > /usr/local/java/jdk1.3.1/solsparc/bin/java -version
        java version "1.3.1-rc1"
        Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1-rc1-b17)
        Java HotSpot(TM) Client VM (build 1.3.1rc1-b17, mixed mode)

        When I debug this program using jdb, and stop at line 10 and then do a 'step',
        it shows line 13, which is really confusing because line 13 is *not* executed at all.

        Using javap to show the bytecode and line table information:
        > /usr/local/java/jdk1.3.1/solsparc/bin/javap -l -c HelloWorld
        Compiled from HelloWorld.java
        public class HelloWorld extends java.lang.Object {
            public HelloWorld();
            public static void main(java.lang.String[]);
        }

        Method HelloWorld()
           0 aload_0
           1 invokespecial #1 <Method java.lang.Object()>
           4 return

        Line numbers for method HelloWorld()
           line 3: 0

        Local variables for method HelloWorld()
           HelloWorld this pc=0, length=5, slot=0

        Method void main(java.lang.String[])
           0 bipush 10
           2 istore_1
           3 getstatic #2 <Field java.io.PrintStream out>
           6 ldc #3 <String "Hello World!">
           8 invokevirtual #4 <Method void println(java.lang.String)>
          11 iload_1
          12 iconst_2
          13 irem
          14 ifne 56
          17 getstatic #2 <Field java.io.PrintStream out>
          20 new #5 <Class java.lang.StringBuffer>
          23 dup
          24 invokespecial #6 <Method java.lang.StringBuffer()>
          27 ldc #7 <String "i = ">
          29 invokevirtual #8 <Method java.lang.StringBuffer append(java.lang.String)>
          32 iload_1
          33 invokevirtual #9 <Method java.lang.StringBuffer append(int)>
          36 ldc #10 <String " is an even number.">
          38 invokevirtual #8 <Method java.lang.StringBuffer append(java.lang.String)>
          41 invokevirtual #11 <Method java.lang.String toString()>
          44 invokevirtual #4 <Method void println(java.lang.String)>
          47 ldc #12 <String "200">
          49 invokestatic #13 <Method int parseInt(java.lang.String)>
          52 pop
          53 goto 92
          56 getstatic #2 <Field java.io.PrintStream out>
          59 new #5 <Class java.lang.StringBuffer>
          62 dup
          63 invokespecial #6 <Method java.lang.StringBuffer()>
          66 ldc #7 <String "i = ">
          68 invokevirtual #8 <Method java.lang.StringBuffer append(java.lang.String)>
          71 iload_1
          72 invokevirtual #9 <Method java.lang.StringBuffer append(int)>
          75 ldc #14 <String " is an odd number.">
          77 invokevirtual #8 <Method java.lang.StringBuffer append(java.lang.String)>
          80 invokevirtual #11 <Method java.lang.String toString()>
          83 invokevirtual #4 <Method void println(java.lang.String)>
          86 ldc2_w #15 <Long 10>
          89 invokestatic #17 <Method void sleep(long)>
          92 goto 104
          95 astore_2
          96 getstatic #2 <Field java.io.PrintStream out>
          99 ldc #19 <String "Exception caught!">
         101 invokevirtual #4 <Method void println(java.lang.String)>
         104 getstatic #2 <Field java.io.PrintStream out>
         107 ldc #20 <String "Bye">
         109 invokevirtual #4 <Method void println(java.lang.String)>
         112 return
        Exception table:
           from to target type
            11 92 95 <Class java.lang.Exception>

        Line numbers for method void main(java.lang.String[])
           line 5: 0
           line 6: 3
           line 8: 11
           line 9: 17
           line 10: 47
           line 12: 56
           line 13: 86
           line 16: 95
           line 19: 104
           line 20: 112

        Local variables for method void main(java.lang.String[])
           java.lang.String[] args pc=0, length=113, slot=0
           int i pc=3, length=109, slot=1
           java.lang.Exception e pc=95, length=9, slot=2

        After executing line 10, bci will be at 92 goto 104, which does not
        associate with any line number. So jdb chooses to show line 13, which
        is the last line that has bci <= 92.

        Request to generate additional line table information to indicate
        appropriate line associated with a catch statement. E.g. bci 92 of
        HelloWorld.main refers to line 15.
         

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                Assignee:
                gafter Neal Gafter
                Reporter:
                mchung Mandy Chung
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