test/201-built-in-exception-detail-messages/src/Main.java - platform/art - Gitiles

 /*
  * Copyright (C) 2012 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 import java.lang.reflect.Array;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;

 public class Main {
   public static void main(String[] args) throws Exception {
     arrayAccess();
     arrayStore();
     classCast();
     classNotFound();
     negativeArraySize();
     nullPointers();
     reflection();
     stringIndex();
   }

   private static void assertEquals(String expected, String actual) {
     if (expected == null && actual == null) {
       return;
     }
     if (expected != null && expected.equals(actual)) {
       return;
     }
     throw new AssertionError("not equal\n" +
                                  "expected: " + expected + "\n" +
                                  "actual:   " + actual);
   }

   private static void fail() {
     throw new AssertionError();
   }

   private static void arrayAccess() throws Exception {
     byte[] bs = new byte[1];
     double[] ds = new double[1];
     Object[] os = new Object[1];

     // aput
     try {
       bs[2] = 0;
       fail();
     } catch (ArrayIndexOutOfBoundsException ex) {
       assertEquals("length=1; index=2", ex.getMessage());
     }

     // aget
     try {
       byte b = bs[2];
       fail();
     } catch (ArrayIndexOutOfBoundsException ex) {
       assertEquals("length=1; index=2", ex.getMessage());
     }

     // aput-wide
     try {
       ds[2] = 0.0;
       fail();
     } catch (ArrayIndexOutOfBoundsException ex) {
       assertEquals("length=1; index=2", ex.getMessage());
     }

     // aget-wide
     try {
       double d = ds[2];
       fail();
     } catch (ArrayIndexOutOfBoundsException ex) {
       assertEquals("length=1; index=2", ex.getMessage());
     }

     // aput-object
     try {
       os[2] = null;
       fail();
     } catch (ArrayIndexOutOfBoundsException ex) {
       assertEquals("length=1; index=2", ex.getMessage());
     }

     // aget-object
     try {
       Object o = os[2];
       fail();
     } catch (ArrayIndexOutOfBoundsException ex) {
       assertEquals("length=1; index=2", ex.getMessage());
     }
   }

   private static void arrayStore() throws Exception {
     try {
       Object[] array = new String[10];
       Object o = new Exception();
       array[0] = o;
       fail();
     } catch (ArrayStoreException ex) {
       assertEquals("java.lang.Exception cannot be stored in an array of type java.lang.String[]",
                    ex.getMessage());
     }

     try {
       Object[] array = new C[10][];
       Object o = new Integer(5);
       array[0] = o;
       fail();
     } catch (ArrayStoreException ex) {
       assertEquals("java.lang.Integer cannot be stored in an array of type Main$C[][]",
                    ex.getMessage());
     }

     try {
       Object[] array = new Float[10][];
       Object o = new C[4];
       array[0] = o;
       fail();
     } catch (ArrayStoreException ex) {
       assertEquals("Main$C[] cannot be stored in an array of type java.lang.Float[][]",
                    ex.getMessage());
     }

     try {
       String[] src = new String[] { null, null, null, null, "hello", "goodbye" };
       Integer[] dst = new Integer[10];
       System.arraycopy(src, 1, dst, 0, 5);
     } catch (ArrayStoreException ex) {
       assertEquals("source[4] of type java.lang.String cannot be stored in destination array of type java.lang.Integer[]",
                    ex.getMessage());
     }

     try {
       String[] src = new String[1];
       int[] dst = new int[1];
       System.arraycopy(src, 0, dst, 0, 1);
     } catch (ArrayStoreException ex) {
       assertEquals("Incompatible types: src=java.lang.String[], dst=int[]", ex.getMessage());
     }

     try {
       float[] src = new float[1];
       Runnable[] dst = new Runnable[1];
       System.arraycopy(src, 0, dst, 0, 1);
     } catch (ArrayStoreException ex) {
       assertEquals("Incompatible types: src=float[], dst=java.lang.Runnable[]", ex.getMessage());
     }

     try {
       boolean[] src = new boolean[1];
       double[][] dst = new double[1][];
       System.arraycopy(src, 0, dst, 0, 1);
     } catch (ArrayStoreException ex) {
       assertEquals("Incompatible types: src=boolean[], dst=double[][]", ex.getMessage());
     }

     try {
       String src = "hello";
       Object[] dst = new Object[1];
       System.arraycopy(src, 0, dst, 0, 1);
     } catch (ArrayStoreException ex) {
       assertEquals("source of type java.lang.String is not an array", ex.getMessage());
     }

     try {
       Object[] src = new Object[1];
       Integer dst = new Integer(5);
       System.arraycopy(src, 0, dst, 0, 1);
     } catch (ArrayStoreException ex) {
       assertEquals("destination of type java.lang.Integer is not an array", ex.getMessage());
     }

     // This test demonstrates that the exception message complains
     // about the source in cases where neither source nor
     // destination is an array.
     try {
       System.arraycopy(new C(), 0, "hello", 0, 1);
     } catch (ArrayStoreException ex) {
       assertEquals("source of type Main$C is not an array", ex.getMessage());
     }
   }

   private static void classCast() throws Exception {
     // Reference types.
     try {
       Object o = new Exception();
       String s = (String) o;
       fail();
     } catch (ClassCastException ex) {
       assertEquals("java.lang.Exception cannot be cast to java.lang.String", ex.getMessage());
     }

     // Arrays of reference types.
     try {
       Object o = (C) makeArray(String.class);
       fail();
     } catch (ClassCastException ex) {
       assertEquals("java.lang.String[] cannot be cast to Main$C", ex.getMessage());
     }

     // Arrays of primitives.
     try {
       Object o = (C) makeArray(float.class);
       fail();
     } catch (ClassCastException ex) {
       assertEquals("float[] cannot be cast to Main$C", ex.getMessage());
     }

     // Multi-dimensional arrays of primitives.
     try {
       Object o = (C) makeArray(char[].class);
       fail();
     } catch (ClassCastException ex) {
       assertEquals("char[][] cannot be cast to Main$C", ex.getMessage());
     }

     // Multi-dimensional arrays of references.
     try {
       Object o = (Object[][][]) makeInteger();
       fail();
     } catch (ClassCastException ex) {
       assertEquals("java.lang.Integer cannot be cast to java.lang.Object[][][]", ex.getMessage());
     }
   }

   static class C { }

   /**
    * Helper for testCastOperator and testCastOperatorWithArrays. It's important that the
    * return type is Object, since otherwise the compiler will just reject the code.
    */
   private static Object makeInteger() {
     return new Integer(5);
   }

   /**
    * Helper for testCastOperatorWithArrays. It's important that
    * the return type is Object.
    */
   private static Object makeArray(Class c) {
     return Array.newInstance(c, 1);
   }

   private static void classNotFound() throws Exception {
     try {
       // There is no such thing as an array of void.
       Class.forName("[V");
       fail();
     } catch (ClassNotFoundException ex) {
       assertEquals("Invalid name: [V", ex.getMessage());
     }

     try {
       // This class name is valid, but doesn't exist.
       Class.forName("package.Class");
       fail();
     } catch (ClassNotFoundException ex) {
       assertEquals("package.Class", ex.getMessage());
     }

     try {
       // This array class name is valid, but the type doesn't exist.
       Class.forName("[[Lpackage.Class;");
       fail();
     } catch (ClassNotFoundException ex) {
       assertEquals("[[Lpackage.Class;", ex.getMessage());
     }
   }

   private static void negativeArraySize() throws Exception {
     try {
       int[] is = new int[-123];
       fail();
     } catch (NegativeArraySizeException ex) {
       assertEquals("-123", ex.getMessage());
     }
   }

   // Defeat the fact that null's are untyped for precise detail message creation with quickening.
   private static Object returnNullObject() {
     return null;
   }

   private static A returnNullA() {
     return null;
   }

   private static void nullPointers() throws Exception {
     // Invoke method.
     try {
       Object o = returnNullObject();
       o.hashCode();
       fail();
     } catch (NullPointerException ex) {
       assertEquals("Attempt to invoke virtual method 'int java.lang.Object.hashCode()' on a null object reference", ex.getMessage());
     }

     // Read field.
     try {
       A a = returnNullA();
       int i = a.i;
       fail();
     } catch (NullPointerException ex) {
       assertEquals("Attempt to read from field 'int A.i' on a null object reference", ex.getMessage());
     }

     // Write field.
     try {
       A a = returnNullA();
       a.i = 1;
       fail();
     } catch (NullPointerException ex) {
       assertEquals("Attempt to write to field 'int A.i' on a null object reference", ex.getMessage());
     }

     // Read array.
     try {
       int[] is = null;
       int i = is[0];
       fail();
     } catch (NullPointerException ex) {
       assertEquals("Attempt to read from null array", ex.getMessage());
     }

     // Write array.
     try {
       int[] is = null;
       is[0] = 1;
       fail();
     } catch (NullPointerException ex) {
       assertEquals("Attempt to write to null array", ex.getMessage());
     }

     // Array length.
     try {
       int[] is = null;
       int i = is.length;
       fail();
     } catch (NullPointerException ex) {
       assertEquals("Attempt to get length of null array", ex.getMessage());
     }
   }

   private static void reflection() throws Exception {
     // Can't assign Integer to a String field.
     try {
       Field field = A.class.getField("b");
       field.set(new A(), 5);
       fail();
     } catch (IllegalArgumentException expected) {
       assertEquals("field A.b has type java.lang.String, got java.lang.Integer",
           expected.getMessage());
     }

     // Can't unbox null to a primitive.
     try {
       Field field = A.class.getField("i");
       field.set(new A(), null);
       fail();
     } catch (IllegalArgumentException expected) {
       assertEquals("field A.i has type int, got null", expected.getMessage());
     }

     // Can't unbox String to a primitive.
     try {
       Field field = A.class.getField("i");
       field.set(new A(), "hello, world!");
       fail();
     } catch (IllegalArgumentException expected) {
       assertEquals("field A.i has type int, got java.lang.String", expected.getMessage());
     }

     // Can't pass an Integer as a String.
     try {
       Method m = A.class.getMethod("m", int.class, String.class);
       m.invoke(new A(), 2, 2);
       fail();
     } catch (IllegalArgumentException expected) {
       assertEquals("method A.m argument 2 has type java.lang.String, got java.lang.Integer",
           expected.getMessage());
     }

     // Can't pass null as an int.
     try {
       Method m = A.class.getMethod("m", int.class, String.class);
       m.invoke(new A(), null, "");
       fail();
     } catch (IllegalArgumentException expected) {
       assertEquals("method A.m argument 1 has type int, got null", expected.getMessage());
     }

     try {
       Method m = String.class.getMethod("charAt", int.class);
       m.invoke("hello"); // Wrong number of arguments.
       fail();
     } catch (IllegalArgumentException iae) {
       assertEquals("Wrong number of arguments; expected 1, got 0", iae.getMessage());
     }
     try {
       Method m = String.class.getMethod("charAt", int.class);
       m.invoke("hello", "world"); // Wrong type.
       fail();
     } catch (IllegalArgumentException iae) {
       assertEquals("method java.lang.String.charAt! argument 1 has type int, got java.lang.String",
           iae.getMessage());
     }
     try {
       Method m = String.class.getMethod("charAt", int.class);
       m.invoke("hello", (Object) null); // Null for a primitive argument.
       fail();
     } catch (IllegalArgumentException iae) {
       assertEquals("method java.lang.String.charAt! argument 1 has type int, got null",
           iae.getMessage());
     }
     try {
       Method m = String.class.getMethod("charAt", int.class);
       m.invoke(new Integer(5)); // Wrong type for 'this'.
       fail();
     } catch (IllegalArgumentException iae) {
       assertEquals("Expected receiver of type java.lang.String, but got java.lang.Integer",
           iae.getMessage());
     }
     try {
       Method m = String.class.getMethod("charAt", int.class);
       m.invoke(null); // Null for 'this'.
       fail();
     } catch (NullPointerException npe) {
       assertEquals("null receiver", npe.getMessage());
     }
   }

   private static void stringIndex() throws Exception {
     // charAt too small.
     try {
       "hello".charAt(-1);
       fail();
     } catch (StringIndexOutOfBoundsException ex) {
       assertEquals("length=5; index=-1", ex.getMessage());
     }

     // charAt too big.
     try {
       "hello".charAt(7);
       fail();
     } catch (StringIndexOutOfBoundsException ex) {
       assertEquals("length=5; index=7", ex.getMessage());
     }

     // substring too big.
     try {
       "hello there".substring(9,14);
       fail();
     } catch (StringIndexOutOfBoundsException ex) {
       assertEquals("length=11; regionStart=9; regionLength=5", ex.getMessage());
     }
   }
 }

 class A {
   public String b;
   public int i;
   public void m(int i, String s) {}
 }
	/*
	* Copyright (C) 2012 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	import java.lang.reflect.Array;
	import java.lang.reflect.Field;
	import java.lang.reflect.Method;

	public class Main {
	public static void main(String[] args) throws Exception {
	arrayAccess();
	arrayStore();
	classCast();
	classNotFound();
	negativeArraySize();
	nullPointers();
	reflection();
	stringIndex();
	}

	private static void assertEquals(String expected, String actual) {
	if (expected == null && actual == null) {
	return;
	}
	if (expected != null && expected.equals(actual)) {
	return;
	}
	throw new AssertionError("not equal\n" +
	"expected: " + expected + "\n" +
	"actual: " + actual);
	}

	private static void fail() {
	throw new AssertionError();
	}

	private static void arrayAccess() throws Exception {
	byte[] bs = new byte[1];
	double[] ds = new double[1];
	Object[] os = new Object[1];

	// aput
	try {
	bs[2] = 0;
	fail();
	} catch (ArrayIndexOutOfBoundsException ex) {
	assertEquals("length=1; index=2", ex.getMessage());
	}

	// aget
	try {
	byte b = bs[2];
	fail();
	} catch (ArrayIndexOutOfBoundsException ex) {
	assertEquals("length=1; index=2", ex.getMessage());
	}

	// aput-wide
	try {
	ds[2] = 0.0;
	fail();
	} catch (ArrayIndexOutOfBoundsException ex) {
	assertEquals("length=1; index=2", ex.getMessage());
	}

	// aget-wide
	try {
	double d = ds[2];
	fail();
	} catch (ArrayIndexOutOfBoundsException ex) {
	assertEquals("length=1; index=2", ex.getMessage());
	}

	// aput-object
	try {
	os[2] = null;
	fail();
	} catch (ArrayIndexOutOfBoundsException ex) {
	assertEquals("length=1; index=2", ex.getMessage());
	}

	// aget-object
	try {
	Object o = os[2];
	fail();
	} catch (ArrayIndexOutOfBoundsException ex) {
	assertEquals("length=1; index=2", ex.getMessage());
	}
	}

	private static void arrayStore() throws Exception {
	try {
	Object[] array = new String[10];
	Object o = new Exception();
	array[0] = o;
	fail();
	} catch (ArrayStoreException ex) {
	assertEquals("java.lang.Exception cannot be stored in an array of type java.lang.String[]",
	ex.getMessage());
	}

	try {
	Object[] array = new C[10][];
	Object o = new Integer(5);
	array[0] = o;
	fail();
	} catch (ArrayStoreException ex) {
	assertEquals("java.lang.Integer cannot be stored in an array of type Main$C[][]",
	ex.getMessage());
	}

	try {
	Object[] array = new Float[10][];
	Object o = new C[4];
	array[0] = o;
	fail();
	} catch (ArrayStoreException ex) {
	assertEquals("Main$C[] cannot be stored in an array of type java.lang.Float[][]",
	ex.getMessage());
	}

	try {
	String[] src = new String[] { null, null, null, null, "hello", "goodbye" };
	Integer[] dst = new Integer[10];
	System.arraycopy(src, 1, dst, 0, 5);
	} catch (ArrayStoreException ex) {
	assertEquals("source[4] of type java.lang.String cannot be stored in destination array of type java.lang.Integer[]",
	ex.getMessage());
	}

	try {
	String[] src = new String[1];
	int[] dst = new int[1];
	System.arraycopy(src, 0, dst, 0, 1);
	} catch (ArrayStoreException ex) {
	assertEquals("Incompatible types: src=java.lang.String[], dst=int[]", ex.getMessage());
	}

	try {
	float[] src = new float[1];
	Runnable[] dst = new Runnable[1];
	System.arraycopy(src, 0, dst, 0, 1);
	} catch (ArrayStoreException ex) {
	assertEquals("Incompatible types: src=float[], dst=java.lang.Runnable[]", ex.getMessage());
	}

	try {
	boolean[] src = new boolean[1];
	double[][] dst = new double[1][];
	System.arraycopy(src, 0, dst, 0, 1);
	} catch (ArrayStoreException ex) {
	assertEquals("Incompatible types: src=boolean[], dst=double[][]", ex.getMessage());
	}

	try {
	String src = "hello";
	Object[] dst = new Object[1];
	System.arraycopy(src, 0, dst, 0, 1);
	} catch (ArrayStoreException ex) {
	assertEquals("source of type java.lang.String is not an array", ex.getMessage());
	}

	try {
	Object[] src = new Object[1];
	Integer dst = new Integer(5);
	System.arraycopy(src, 0, dst, 0, 1);
	} catch (ArrayStoreException ex) {
	assertEquals("destination of type java.lang.Integer is not an array", ex.getMessage());
	}

	// This test demonstrates that the exception message complains
	// about the source in cases where neither source nor
	// destination is an array.
	try {
	System.arraycopy(new C(), 0, "hello", 0, 1);
	} catch (ArrayStoreException ex) {
	assertEquals("source of type Main$C is not an array", ex.getMessage());
	}
	}

	private static void classCast() throws Exception {
	// Reference types.
	try {
	Object o = new Exception();
	String s = (String) o;
	fail();
	} catch (ClassCastException ex) {
	assertEquals("java.lang.Exception cannot be cast to java.lang.String", ex.getMessage());
	}

	// Arrays of reference types.
	try {
	Object o = (C) makeArray(String.class);
	fail();
	} catch (ClassCastException ex) {
	assertEquals("java.lang.String[] cannot be cast to Main$C", ex.getMessage());
	}

	// Arrays of primitives.
	try {
	Object o = (C) makeArray(float.class);
	fail();
	} catch (ClassCastException ex) {
	assertEquals("float[] cannot be cast to Main$C", ex.getMessage());
	}

	// Multi-dimensional arrays of primitives.
	try {
	Object o = (C) makeArray(char[].class);
	fail();
	} catch (ClassCastException ex) {
	assertEquals("char[][] cannot be cast to Main$C", ex.getMessage());
	}

	// Multi-dimensional arrays of references.
	try {
	Object o = (Object[][][]) makeInteger();
	fail();
	} catch (ClassCastException ex) {
	assertEquals("java.lang.Integer cannot be cast to java.lang.Object[][][]", ex.getMessage());
	}
	}

	static class C { }

	/**
	* Helper for testCastOperator and testCastOperatorWithArrays. It's important that the
	* return type is Object, since otherwise the compiler will just reject the code.
	*/
	private static Object makeInteger() {
	return new Integer(5);
	}

	/**
	* Helper for testCastOperatorWithArrays. It's important that
	* the return type is Object.
	*/
	private static Object makeArray(Class c) {
	return Array.newInstance(c, 1);
	}

	private static void classNotFound() throws Exception {
	try {
	// There is no such thing as an array of void.
	Class.forName("[V");
	fail();
	} catch (ClassNotFoundException ex) {
	assertEquals("Invalid name: [V", ex.getMessage());
	}

	try {
	// This class name is valid, but doesn't exist.
	Class.forName("package.Class");
	fail();
	} catch (ClassNotFoundException ex) {
	assertEquals("package.Class", ex.getMessage());
	}

	try {
	// This array class name is valid, but the type doesn't exist.
	Class.forName("[[Lpackage.Class;");
	fail();
	} catch (ClassNotFoundException ex) {
	assertEquals("[[Lpackage.Class;", ex.getMessage());
	}
	}

	private static void negativeArraySize() throws Exception {
	try {
	int[] is = new int[-123];
	fail();
	} catch (NegativeArraySizeException ex) {
	assertEquals("-123", ex.getMessage());
	}
	}

	// Defeat the fact that null's are untyped for precise detail message creation with quickening.
	private static Object returnNullObject() {
	return null;
	}

	private static A returnNullA() {
	return null;
	}

	private static void nullPointers() throws Exception {
	// Invoke method.
	try {
	Object o = returnNullObject();
	o.hashCode();
	fail();
	} catch (NullPointerException ex) {
	assertEquals("Attempt to invoke virtual method 'int java.lang.Object.hashCode()' on a null object reference", ex.getMessage());
	}

	// Read field.
	try {
	A a = returnNullA();
	int i = a.i;
	fail();
	} catch (NullPointerException ex) {
	assertEquals("Attempt to read from field 'int A.i' on a null object reference", ex.getMessage());
	}

	// Write field.
	try {
	A a = returnNullA();
	a.i = 1;
	fail();
	} catch (NullPointerException ex) {
	assertEquals("Attempt to write to field 'int A.i' on a null object reference", ex.getMessage());
	}

	// Read array.
	try {
	int[] is = null;
	int i = is[0];
	fail();
	} catch (NullPointerException ex) {
	assertEquals("Attempt to read from null array", ex.getMessage());
	}

	// Write array.
	try {
	int[] is = null;
	is[0] = 1;
	fail();
	} catch (NullPointerException ex) {
	assertEquals("Attempt to write to null array", ex.getMessage());
	}

	// Array length.
	try {
	int[] is = null;
	int i = is.length;
	fail();
	} catch (NullPointerException ex) {
	assertEquals("Attempt to get length of null array", ex.getMessage());
	}
	}

	private static void reflection() throws Exception {
	// Can't assign Integer to a String field.
	try {
	Field field = A.class.getField("b");
	field.set(new A(), 5);
	fail();
	} catch (IllegalArgumentException expected) {
	assertEquals("field A.b has type java.lang.String, got java.lang.Integer",
	expected.getMessage());
	}

	// Can't unbox null to a primitive.
	try {
	Field field = A.class.getField("i");
	field.set(new A(), null);
	fail();
	} catch (IllegalArgumentException expected) {
	assertEquals("field A.i has type int, got null", expected.getMessage());
	}

	// Can't unbox String to a primitive.
	try {
	Field field = A.class.getField("i");
	field.set(new A(), "hello, world!");
	fail();
	} catch (IllegalArgumentException expected) {
	assertEquals("field A.i has type int, got java.lang.String", expected.getMessage());
	}

	// Can't pass an Integer as a String.
	try {
	Method m = A.class.getMethod("m", int.class, String.class);
	m.invoke(new A(), 2, 2);
	fail();
	} catch (IllegalArgumentException expected) {
	assertEquals("method A.m argument 2 has type java.lang.String, got java.lang.Integer",
	expected.getMessage());
	}

	// Can't pass null as an int.
	try {
	Method m = A.class.getMethod("m", int.class, String.class);
	m.invoke(new A(), null, "");
	fail();
	} catch (IllegalArgumentException expected) {
	assertEquals("method A.m argument 1 has type int, got null", expected.getMessage());
	}

	try {
	Method m = String.class.getMethod("charAt", int.class);
	m.invoke("hello"); // Wrong number of arguments.
	fail();
	} catch (IllegalArgumentException iae) {
	assertEquals("Wrong number of arguments; expected 1, got 0", iae.getMessage());
	}
	try {
	Method m = String.class.getMethod("charAt", int.class);
	m.invoke("hello", "world"); // Wrong type.
	fail();
	} catch (IllegalArgumentException iae) {
	assertEquals("method java.lang.String.charAt! argument 1 has type int, got java.lang.String",
	iae.getMessage());
	}
	try {
	Method m = String.class.getMethod("charAt", int.class);
	m.invoke("hello", (Object) null); // Null for a primitive argument.
	fail();
	} catch (IllegalArgumentException iae) {
	assertEquals("method java.lang.String.charAt! argument 1 has type int, got null",
	iae.getMessage());
	}
	try {
	Method m = String.class.getMethod("charAt", int.class);
	m.invoke(new Integer(5)); // Wrong type for 'this'.
	fail();
	} catch (IllegalArgumentException iae) {
	assertEquals("Expected receiver of type java.lang.String, but got java.lang.Integer",
	iae.getMessage());
	}
	try {
	Method m = String.class.getMethod("charAt", int.class);
	m.invoke(null); // Null for 'this'.
	fail();
	} catch (NullPointerException npe) {
	assertEquals("null receiver", npe.getMessage());
	}
	}

	private static void stringIndex() throws Exception {
	// charAt too small.
	try {
	"hello".charAt(-1);
	fail();
	} catch (StringIndexOutOfBoundsException ex) {
	assertEquals("length=5; index=-1", ex.getMessage());
	}

	// charAt too big.
	try {
	"hello".charAt(7);
	fail();
	} catch (StringIndexOutOfBoundsException ex) {
	assertEquals("length=5; index=7", ex.getMessage());
	}

	// substring too big.
	try {
	"hello there".substring(9,14);
	fail();
	} catch (StringIndexOutOfBoundsException ex) {
	assertEquals("length=11; regionStart=9; regionLength=5", ex.getMessage());
	}
	}
	}

	class A {
	public String b;
	public int i;
	public void m(int i, String s) {}
	}