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  1. JDK
  2. JDK-8074802

Compiler throws NullPointerException for lambda with unboxing

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    • Icon: Bug Bug
    • Resolution: Duplicate
    • Icon: P4 P4
    • None
    • 8u31
    • tools
    • x86
    • os_x

      FULL PRODUCT VERSION :
      java version "1.8.0_31"
      Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
      Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)


      ADDITIONAL OS VERSION INFORMATION :
      MacOS 10.10.2 (14C109)

      A DESCRIPTION OF THE PROBLEM :
      Compiler throws NullPointerException for the following code:



      ERROR MESSAGES/STACK TRACES THAT OCCUR :
      $ javac CompileBug.java
      An exception has occurred in the compiler (1.8.0_31). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you.
      java.lang.NullPointerException
      at com.sun.tools.javac.code.Types.isConvertible(Types.java:290)
      at com.sun.tools.javac.comp.Check.assertConvertible(Check.java:922)
      at com.sun.tools.javac.comp.Check.checkMethod(Check.java:876)
      at com.sun.tools.javac.comp.Attr.checkMethod(Attr.java:3838)
      at com.sun.tools.javac.comp.Attr.checkIdInternal(Attr.java:3615)
      at com.sun.tools.javac.comp.Attr.checkMethodIdInternal(Attr.java:3522)
      at com.sun.tools.javac.comp.Attr.checkMethodId(Attr.java:3501)
      at com.sun.tools.javac.comp.Attr.checkId(Attr.java:3488)
      at com.sun.tools.javac.comp.Attr.visitSelect(Attr.java:3370)
      at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:1897)
      at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
      at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1843)
      at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1465)
      at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
      at com.sun.tools.javac.comp.Attr.visitReturn(Attr.java:1704)
      at com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1384)
      at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
      at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:676)
      at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:692)
      at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1142)
      at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:909)
      at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
      at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:676)
      at com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:1035)
      at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:778)
      at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
      at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:676)
      at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:4342)
      at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4252)
      at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4181)
      at com.sun.tools.javac.comp.Attr.attrib(Attr.java:4156)
      at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1248)
      at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:901)
      at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:860)
      at com.sun.tools.javac.main.Main.compile(Main.java:523)
      at com.sun.tools.javac.main.Main.compile(Main.java:381)
      at com.sun.tools.javac.main.Main.compile(Main.java:370)
      at com.sun.tools.javac.main.Main.compile(Main.java:361)
      at com.sun.tools.javac.Main.compile(Main.java:56)
      at com.sun.tools.javac.Main.main(Main.java:42)


      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      import java.util.List;

      public class CompileBug {
          public int reduce(List<String> list) {
              return list.stream().reduce(0, (sum, string) -> sum + string.length(), (a, b) -> a + b);
          }
      }
      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      Have the method return an Integer instead of an int

      // This works
      public class CompileBug {
          public Integer reduce(List<String> list) {
              return list.stream().reduce(0, (sum, string) -> sum + string.length(), (a, b) -> a + b);
          }
      }

            pardesha Pardeep Sharma
            webbuggrp Webbug Group
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              Created:
              Updated:
              Resolved: