Bugfix for 3008828: throw null

mgricken · mgricken · commit 3b9696a707d2 · 2010-05-29T11:35:16.000Z
http://sourceforge.net/tracker/index.php?func=detail&aid=3008828&group_id=44253&atid=438935 Fixed in DynamicJava: As per Java Language Specification (JLS): http://java.sun.com/docs/books/jls/third_edition/html/statements.html#14.18 "If evaluation of the Expression completes normally, producing a null value, then an instance V of class NullPointerException is created and thrown instead of null." M dynamicjava/src/edu/rice/cs/dynamicjava/interpreter/StatementEvaluator.java M drjava/lib/dynamicjava-base.jar M drjava/src/edu/rice/cs/drjava/model/repl/JavaInterpreterTest.java git-svn-id: file:///tmp/test-svn/trunk@5261 fe72c1cf-3628-48e9-8b72-1c46755d3cff
diff --git a/drjava/lib/dynamicjava-base.jar b/drjava/lib/dynamicjava-base.jar
diff --git a/drjava/src/edu/rice/cs/drjava/model/repl/JavaInterpreterTest.java b/drjava/src/edu/rice/cs/drjava/model/repl/JavaInterpreterTest.java
@@ -555,4 +555,24 @@ public void testUserDefinedVoidMethod() throws InterpreterException {
      Object result = interpret("public void foo() {}; foo()");
      assertSame("Should have returned NO_RESULT.", null, result);
    }
+  
+  /** Test throwing null, for bug 3008828. */
+  public void testThrowNull() throws InterpreterException {
+    try {
+      _interpreter.interpret("throw null");
+      fail("Should have thrown an EvaluatorException with a NullPointerException as cause.");
+    }
+    catch(Throwable t) {
+      if ((t == null) || (!(t instanceof EvaluatorException))) {
+        fail("Should have thrown an EvaluatorException with a NullPointerException as cause.");
+      }
+      else {
+        Throwable cause = t.getCause();
+        if (!(cause instanceof NullPointerException)) {
+          fail("Should have thrown an EvaluatorException with a NullPointerException as cause.");
+        }
+      }
+    }
+  }
+
 }
diff --git a/dynamicjava/src/edu/rice/cs/dynamicjava/interpreter/StatementEvaluator.java b/dynamicjava/src/edu/rice/cs/dynamicjava/interpreter/StatementEvaluator.java
@@ -305,6 +305,15 @@ public Object next() {
   
   @Override public Result visit(ThrowStatement node) {
     Throwable t = (Throwable) new ExpressionEvaluator(_bindings, _opt).value(node.getExpression());
+    // bug fix for DrJava bug 3008828
+    if (t == null) {
+        // as per Java Language Specification (JLS):
+        // http://java.sun.com/docs/books/jls/third_edition/html/statements.html#14.18
+        // "If evaluation of the Expression completes normally, producing a null value,
+        // then an instance V� of class NullPointerException is created and thrown instead of null." 
+        t = new NullPointerException();
+        t.setStackTrace(new StackTraceElement[0]);
+    }
     throw new WrappedException(new EvaluatorException(t));
   }
 
