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  1. JDK
  2. JDK-4045970

constant expression is not executed during compilation

    Details

    • Subcomponent:
    • CPU:
      sparc
    • OS:
      solaris_2.5

      Description



      Name: ngC57085 Date: 04/18/97



      Java compiler (JDK1.1.2) does not execute constant expressions
      while compile condition expression.

      JLS (14.19) says:

      "
      A while statement can complete normally iff at least one of the following
      is true:
           The while statement is reachable and the condition expression is not
           a constant expression with value true.
           
           There is a reachable break statement that exits the while statement.
      "

      A while statement cannot complete normally if the condition expression
      is a constant expression with value true.

      Test stmt14104, where condition expression is a constant expression with
      value true, is compiled successfully by JDK1.1.2 instead of error message.

      > javac112 stmt14104.java
      >

      ------------------------stmt14104--------------
      import java.io.PrintStream;

      public class stmt14104 {
        public static void main(String argv[]) {
           System.exit(run(argv, System.out) + 95/*STATUS_TEMP*/);
        }
        public static int run(String argv[],PrintStream out) {
           int a1 = 1;
           int a2 = 1;
           int a3 = 1;
           final boolean b = true;
           a1 = 2;
           while (b) {
              a2++;
           }
           a3 = 2;
           return 2/*STATUS_FAILED*/;
        }
      }
      --------------------------------------

      And test stmt14104a, where condition expression is literal true,
      is not compiled by JDK1.1.2.

      > javac112 stmt14104a.java
      stmt14104a.java:15: Statement not reached.
           a3 = 2;
           ^
      1 error
      >
      ------------------------stmt14104a--------------
      import java.io.PrintStream;

      public class stmt14104a {
        public static void main(String argv[]) {
           System.exit(run(argv, System.out) + 95/*STATUS_TEMP*/);
        }
        public static int run(String argv[],PrintStream out) {
           int a1 = 1;
           int a2 = 1;
           int a3 = 1;
           a1 = 2;
           while (true) {
              a2++;
           }
           a3 = 2;
           return 2/*STATUS_FAILED*/;
        }
      }
      --------------------------------------


      ======================================================================

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            • Assignee:
              tturnidgsunw Todd Turnidge (Inactive)
              Reporter:
              duke J. Duke (Inactive)
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