JDK-8044737 : Lambda: NPE while obtaining method reference through lambda expression
- Type: Bug
- Component: tools
- Sub-Component: javac
- Affected Version: 8,9
- Priority: P2
- Status: Closed
- Resolution: Fixed
- Submitted: 2014-06-03
- Updated: 2016-01-22
- Resolved: 2014-06-24
The Version table provides details related to the release that this issue/RFE will be addressed.
Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.
To download the current JDK release, click here.
Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.
To download the current JDK release, click here.
| JDK 8 | JDK 9 |
|---|---|
8u40Fixed  |
9 b22Fixed |
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Description
Code:
$ cat Test.java
public class Test {
interface Constructor {
MyTest execute();
}
class MyTest {
MyTest() { System.out.println("Constructor executed"); }
}
public Constructor getConstructor() {
return getConstructor(() -> { return MyTest::new; });
}
public static void main(String argv[]) {
Test t = new Test();
MyTest mytest = t.getConstructor().execute();
}
Constructor getConstructor(Wrapper arg) {
return arg.unwrap();
}
interface Wrapper {
Constructor unwrap();
}
}
Generates NullPointerException on compilation:
$ javac Test.java
An exception has occurred in the compiler (1.9.0-internal). 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.jvm.Code.emitop0(Code.java:563)
at com.sun.tools.javac.jvm.Items$SelfItem.load(Items.java:367)
at com.sun.tools.javac.jvm.Gen.genArgs(Gen.java:959)
at com.sun.tools.javac.jvm.Gen.visitApply(Gen.java:1898)
at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1459)
at com.sun.tools.javac.jvm.Gen.genExpr(Gen.java:940)
at com.sun.tools.javac.jvm.Gen.visitReturn(Gen.java:1856)
at com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1378)
at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:730)
at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:765)
at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:751)
at com.sun.tools.javac.jvm.Gen.genStats(Gen.java:802)
at com.sun.tools.javac.jvm.Gen.visitBlock(Gen.java:1151)
at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:903)
at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:730)
at com.sun.tools.javac.jvm.Gen.genStat(Gen.java:765)
at com.sun.tools.javac.jvm.Gen.genMethod(Gen.java:1024)
at com.sun.tools.javac.jvm.Gen.visitMethodDef(Gen.java:987)
at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:772)
at com.sun.tools.javac.jvm.Gen.genDef(Gen.java:730)
at com.sun.tools.javac.jvm.Gen.genClass(Gen.java:2518)
at com.sun.tools.javac.main.JavaCompiler.genCode(JavaCompiler.java:744)
at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1571)
at com.sun.tools.javac.main.JavaCompiler.generate(JavaCompiler.java:1535)
at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:906)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:865)
at com.sun.tools.javac.main.Main.compile(Main.java:521)
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)
Changing 'getConstructor()' method to implementation without lambda wrapper works good:
public Constructor getConstructor() {
return MyTest::new;
}
$ javac Test.java
$ java Test
Constructor executed
Comments
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