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  1. JDK
  2. JDK-8042405

Can't compile Lambda referencing final variable initialized on constructor

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    • Subcomponent:
    • CPU:
      x86_64
    • OS:
      linux

      Description

      FULL PRODUCT VERSION :
      java version "1.8.0_05"
      Java(TM) SE Runtime Environment (build 1.8.0_05-b13)
      Java HotSpot(TM) 64-Bit Server VM (build 25.5-b02, mixed mode)

      ADDITIONAL OS VERSION INFORMATION :
      Linux 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:11:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

      A DESCRIPTION OF THE PROBLEM :
      When a Lambda expression defined as a class instance references a final variable that is initialized only inside a constructor, but without calling "this." before the variable, the compiler throws a compilation error.

      With the "this." before the variable, the compiler works fine.

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      See provided source code to compile.


      ERROR MESSAGES/STACK TRACES THAT OCCUR :
      Compiling 2 source files to /home/bruno/javabug/build/classes
      /home/bruno/javabug/src/FooBar.java:14: error: variable foobar might not have been initialized
              System.out.println(foobar); // throws compilation error
      1 error

      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      /**
       * @author bruno.borges@oracle.com
       */
      public class FooBar {

          private final String foobar;

          public FooBar() {
              foobar = "foobar";
          }

          private final java.util.function.Function ds = n -> {
              System.out.println(this.foobar); // compiles successfuly
              System.out.println(foobar); // throws compilation error: "variable foobar might not have been initialized"

              return foobar;
          };

      }

      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      The reference to the variable must be preceded with "this." or else the compiler throws a compilation error.

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              Assignee:
              dlsmith Dan Smith
              Reporter:
              webbuggrp Webbug Group
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                Created:
                Updated:
                Resolved: