Java Code Examples for java.lang.invoke.MethodHandles.Lookup

static MethodHandle[] makeLists() {
    ArrayList<MethodHandle> lists = new ArrayList<>();
    MethodHandles.Lookup lookup = IMPL_LOOKUP;
    for (;;) {
        int nargs = lists.size();
        MethodType type = MethodType.genericMethodType(nargs).changeReturnType(List.class);
        String name = "list";
        MethodHandle list = null;
        try {
            list = lookup.findStatic(ValueConversions.class, name, type);
        } catch (ReflectiveOperationException ex) {
            // break from loop!
        }
        if (list == null)  break;
        lists.add(list);
    }
    assertTrue(lists.size() == 11);  // current number of methods
    return lists.toArray(new MethodHandle[0]);
}
 

public static void main(String[] args) throws Throwable {
    Lookup LOOKUP = T3.lookup();
    Class<IllegalAccessException> IAE = IllegalAccessException.class;

    assertFailure(IAE, () -> LOOKUP.findVirtual(T1.class, "m1", MethodType.methodType(void.class)));
    assertFailure(IAE, () -> LOOKUP.findStatic(T1.class, "m2", MethodType.methodType(void.class)));

    assertSuccess(() -> LOOKUP.findVirtual(T2.class, "m1", MethodType.methodType(void.class)));
    assertSuccess(() -> LOOKUP.findVirtual(T3.class, "m1", MethodType.methodType(void.class)));

    assertSuccess(() -> LOOKUP.findStatic(T2.class, "m2", MethodType.methodType(void.class)));
    assertSuccess(() -> LOOKUP.findStatic(T3.class, "m2", MethodType.methodType(void.class)));

    assertFailure(IAE, () -> LOOKUP.unreflect(T1.class.getDeclaredMethod("m1")));
    assertFailure(IAE, () -> LOOKUP.unreflect(T1.class.getDeclaredMethod("m2")));

    System.out.println("TEST PASSED");
}
 

static MethodHandle[] makeArrays() {
    ArrayList<MethodHandle> arrays = new ArrayList<>();
    MethodHandles.Lookup lookup = IMPL_LOOKUP;
    for (;;) {
        int nargs = arrays.size();
        MethodType type = MethodType.genericMethodType(nargs).changeReturnType(Object[].class);
        String name = "array";
        MethodHandle array = null;
        try {
            array = lookup.findStatic(ValueConversions.class, name, type);
        } catch (ReflectiveOperationException ex) {
            // break from loop!
        }
        if (array == null)  break;
        arrays.add(array);
    }
    assertTrue(arrays.size() == 11);  // current number of methods
    return arrays.toArray(new MethodHandle[0]);
}
 

public void testGetter(int testMode) throws Throwable {
    Lookup lookup = PRIVATE;  // FIXME: test more lookups than this one
    for (Object[] c : HasFields.CASES) {
        boolean positive = (c[1] != Error.class);
        testGetter(positive, lookup, c[0], c[1], testMode);
        if (positive)
            testGetter(positive, lookup, c[0], c[1], testMode | TEST_NPE);
    }
    testGetter(true, lookup,
               new Object[]{ true,  System.class, "out", java.io.PrintStream.class },
               System.out, testMode);
    for (int isStaticN = 0; isStaticN <= 1; isStaticN++) {
        testGetter(false, lookup,
                   new Object[]{ (isStaticN != 0), System.class, "bogus", char.class },
                   null, testMode);
    }
}
 

public static void main(String... args) throws Throwable {
    // Get a full power lookup
    Lookup lookup1 =  MethodHandles.lookup();
    MethodHandle mh1 = lookup1.findStatic(lookup1.lookupClass(),
                                          "foo",
                                          methodType(String.class));
    assertEquals((String) mh1.invokeExact(), foo());

    Method lookupMethod =  MethodHandles.class.getMethod("lookup");
    System.out.println("reflection method: " + lookupMethod);
    if (!lookupMethod.getName().equals("lookup")) {
        throw new RuntimeException("Unexpected name: " + lookupMethod.getName());
    }

    // Get a full power Lookup reflectively.
    Lookup lookup2 = (Lookup) lookupMethod.invoke(null);
    assertEquals(lookup1.lookupClass(), lookup2.lookupClass());
    assertEquals(lookup1.lookupModes(), lookup2.lookupModes());
    MethodHandle mh2 = lookup2.findStatic(lookup2.lookupClass(),
                                         "foo",
                                          methodType(String.class));
    assertEquals((String) mh2.invokeExact(), foo());
}
 

static MethodHandle[] makeArrays() {
    ArrayList<MethodHandle> arrays = new ArrayList<>();
    MethodHandles.Lookup lookup = IMPL_LOOKUP;
    for (;;) {
        int nargs = arrays.size();
        MethodType type = MethodType.genericMethodType(nargs).changeReturnType(Object[].class);
        String name = "array";
        MethodHandle array = null;
        try {
            array = lookup.findStatic(ValueConversions.class, name, type);
        } catch (ReflectiveOperationException ex) {
            // break from loop!
        }
        if (array == null)  break;
        arrays.add(array);
    }
    assertTrue(arrays.size() == 11);  // current number of methods
    return arrays.toArray(new MethodHandle[0]);
}
 

/**
 * Produces a {@link MethodHandle} using either the context or {@link #targetLoader} class
 * loader, depending on {@code target}.
 */
private MethodHandle toMethodHandle(Lookup lookup, Handle asmHandle, boolean target)
    throws ReflectiveOperationException {
  Class<?> owner = loadFromInternal(asmHandle.getOwner());
  MethodType signature =
      MethodType.fromMethodDescriptorString(
          asmHandle.getDesc(),
          target ? targetLoader : Thread.currentThread().getContextClassLoader());
  switch (asmHandle.getTag()) {
    case Opcodes.H_INVOKESTATIC:
      return lookup.findStatic(owner, asmHandle.getName(), signature);
    case Opcodes.H_INVOKEVIRTUAL:
    case Opcodes.H_INVOKEINTERFACE:
      return lookup.findVirtual(owner, asmHandle.getName(), signature);
    case Opcodes.H_INVOKESPECIAL: // we end up calling these using invokevirtual
      return lookup.findSpecial(owner, asmHandle.getName(), signature, owner);
    case Opcodes.H_NEWINVOKESPECIAL:
      return lookup.findConstructor(owner, signature);
    default:
      throw new UnsupportedOperationException("Cannot resolve " + asmHandle);
  }
}
 

/** 
 * For a particular type name, get the JCasClassInfo
 *   - by fetching the cached value
 *   - by loading the class
 *   - return null if no JCas class for this name 
 * only called for non-Pear callers
 * @param ti -
 * @param cl -
 * @param type2jcci -
 * @param lookup -
 * @return - jcci or null, if no JCas class for this type was able to be loaded
 */
public static JCasClassInfo getOrCreateJCasClassInfo(
    TypeImpl ti, 
    ClassLoader cl, 
    Map<String, JCasClassInfo> type2jcci, 
    Lookup lookup) {
  
  
  JCasClassInfo jcci = type2jcci.get(ti.getJCasClassName());

  if (jcci == null) {
    jcci = maybeCreateJCasClassInfo(ti, cl, type2jcci, lookup);
  }
  
  // do this setup for new type systems using previously loaded jcci, as well as
  // for new jccis
  if (jcci != null && jcci.jcasType >= 0) {
    ti.getTypeSystem().setJCasRegisteredType(jcci.jcasType, ti);
  }
  return jcci;
}
 

public static CallSite constructorBootstrap(Lookup lookup, String selector,
		MethodType type, String referenceString) throws Throwable {
	Reference reference = Reference.factory.value_(referenceString);
	Constructor constructor = ImageBootstrapper.systemMapping.classMappingAtReference_(reference).identityClass().getConstructor();
	MethodHandle constructorHandle = lookup.unreflectConstructor(constructor);
	return new ConstantCallSite(constructorHandle.asType(type));
}
 

public void testRunnableProxy0() throws Throwable {
    if (CAN_SKIP_WORKING)  return;
    startTest("testRunnableProxy");
    MethodHandles.Lookup lookup = MethodHandles.lookup();
    MethodHandle run = lookup.findStatic(lookup.lookupClass(), "runForRunnable", MethodType.methodType(void.class));
    Runnable r = MethodHandleProxies.asInterfaceInstance(Runnable.class, run);
    testRunnableProxy(r);
    assertCalled("runForRunnable");
}
 

public void testFindSpecial0() throws Throwable {
    if (CAN_SKIP_WORKING)  return;
    startTest("findSpecial");
    testFindSpecial(SubExample.class, Example.class, void.class, "v0");
    testFindSpecial(SubExample.class, Example.class, void.class, "pkg_v0");
    testFindSpecial(RemoteExample.class, PubExample.class, void.class, "Pub/pro_v0");
    // Do some negative testing:
    for (Lookup lookup : new Lookup[]{ PRIVATE, EXAMPLE, PACKAGE, PUBLIC }) {
        testFindSpecial(false, lookup, Object.class, Example.class, void.class, "v0");
        testFindSpecial(false, lookup, SubExample.class, Example.class, void.class, "bogus");
        testFindSpecial(false, lookup, SubExample.class, Example.class, void.class, "<init>", int.class);
        testFindSpecial(false, lookup, SubExample.class, Example.class, void.class, "<init>", Void.class);
        testFindSpecial(false, lookup, SubExample.class, Example.class, void.class, "s0");
    }
}
 

void testFindConstructor(boolean positive, Lookup lookup,
                         Class<?> defc, Class<?>... params) throws Throwable {
    countTest(positive);
    MethodType type = MethodType.methodType(void.class, params);
    MethodHandle target = null;
    Exception noAccess = null;
    try {
        if (verbosity >= 4)  System.out.println("lookup via "+lookup+" of "+defc+" <init>"+type);
        target = lookup.findConstructor(defc, type);
    } catch (ReflectiveOperationException ex) {
        noAccess = ex;
        assertTrue(noAccess.getClass().getName(), noAccess instanceof IllegalAccessException);
    }
    if (verbosity >= 3)
        System.out.println("findConstructor "+defc.getName()+".<init>/"+type+" => "+target
                           +(target == null ? "" : target.type())
                           +(noAccess == null ? "" : " !! "+noAccess));
    if (positive && noAccess != null)  throw noAccess;
    assertEquals(positive ? "positive test" : "negative test erroneously passed", positive, target != null);
    if (!positive)  return; // negative test failed as expected
    assertEquals(type.changeReturnType(defc), target.type());
    Object[] args = randomArgs(params);
    printCalled(target, defc.getSimpleName(), args);
    Object obj = target.invokeWithArguments(args);
    if (!(defc == Example.class && params.length < 2))
        assertCalled(defc.getSimpleName()+".<init>", args);
    assertTrue("instance of "+defc.getName(), defc.isInstance(obj));
}
 

private static boolean lookupsEqual(final Lookup l1, final Lookup l2) {
    if(l1 == l2) {
        return true;
    }
    if(l1.lookupClass() != l2.lookupClass()) {
        return false;
    }
    return l1.lookupModes() == l2.lookupModes();
}
 

void testBind(boolean positive, Lookup lookup, Class<?> defc, Class<?> ret, String name, Class<?>... params) throws Throwable {
    countTest(positive);
    String methodName = name.substring(1 + name.indexOf('/'));  // foo/bar => foo
    MethodType type = MethodType.methodType(ret, params);
    Object receiver = randomArg(defc);
    MethodHandle target = null;
    Exception noAccess = null;
    try {
        if (verbosity >= 4)  System.out.println("lookup via "+lookup+" of "+defc+" "+name+type);
        target = maybeMoveIn(lookup, defc).bind(receiver, methodName, type);
    } catch (ReflectiveOperationException ex) {
        noAccess = ex;
        assertExceptionClass(
            (name.contains("bogus") || INIT_REF_CAUSES_NSME && name.contains("<init>"))
            ?   NoSuchMethodException.class
            :   IllegalAccessException.class,
            noAccess);
        if (verbosity >= 5)  ex.printStackTrace(System.out);
    }
    if (verbosity >= 3)
        System.out.println("bind "+receiver+"."+name+"/"+type+" => "+target
                +(noAccess == null ? "" : " !! "+noAccess));
    if (positive && noAccess != null)  throw noAccess;
    assertEquals(positive ? "positive test" : "negative test erroneously passed", positive, target != null);
    if (!positive)  return; // negative test failed as expected
    assertEquals(type, target.type());
    Object[] args = randomArgs(params);
    printCalled(target, name, args);
    target.invokeWithArguments(args);
    Object[] argsWithReceiver = cat(array(Object[].class, receiver), args);
    assertCalled(name, argsWithReceiver);
    if (verbosity >= 1)
        System.out.print(':');
}
 

@Test
public void testUserClassInSignature() throws Throwable {
    if (CAN_SKIP_WORKING)  return;
    startTest("testUserClassInSignature");
    Lookup lookup = MethodHandles.lookup();
    String name; MethodType mt; MethodHandle mh;
    Object[] args;

    // Try a static method.
    name = "userMethod";
    mt = MethodType.methodType(Example.class, Object.class, String.class, int.class);
    mh = lookup.findStatic(lookup.lookupClass(), name, mt);
    assertEquals(mt, mh.type());
    assertEquals(Example.class, mh.type().returnType());
    args = randomArgs(mh.type().parameterArray());
    mh.invokeWithArguments(args);
    assertCalled(name, args);

    // Try a virtual method.
    name = "v2";
    mt = MethodType.methodType(Object.class, Object.class, int.class);
    mh = lookup.findVirtual(Example.class, name, mt);
    assertEquals(mt, mh.type().dropParameterTypes(0,1));
    assertTrue(mh.type().parameterList().contains(Example.class));
    args = randomArgs(mh.type().parameterArray());
    mh.invokeWithArguments(args);
    assertCalled(name, args);
}
 

private static NashornCallSiteDescriptor get(final MethodHandles.Lookup lookup, final String operator, final String operand, final MethodType methodType, final int flags) {
    final NashornCallSiteDescriptor csd = new NashornCallSiteDescriptor(lookup, operator, operand, methodType, flags);
    // Many of these call site descriptors are identical (e.g. every getter for a property color will be
    // "dyn:getProp:color(Object)Object", so it makes sense canonicalizing them.
    final ConcurrentMap<NashornCallSiteDescriptor, NashornCallSiteDescriptor> classCanonicals = canonicals.get(lookup.lookupClass());
    final NashornCallSiteDescriptor canonical = classCanonicals.putIfAbsent(csd, csd);
    return canonical != null ? canonical : csd;
}
 

public void testRunnableProxy0() throws Throwable {
    if (CAN_SKIP_WORKING)  return;
    startTest("testRunnableProxy");
    MethodHandles.Lookup lookup = MethodHandles.lookup();
    MethodHandle run = lookup.findStatic(lookup.lookupClass(), "runForRunnable", MethodType.methodType(void.class));
    Runnable r = MethodHandleProxies.asInterfaceInstance(Runnable.class, run);
    testRunnableProxy(r);
    assertCalled("runForRunnable");
}
 

public void testSetter(int testMode) throws Throwable {
    Lookup lookup = PRIVATE;  // FIXME: test more lookups than this one
    startTest("unreflectSetter");
    for (Object[] c : HasFields.CASES) {
        boolean positive = (c[1] != Error.class);
        testSetter(positive, lookup, c[0], c[1], testMode);
        if (positive)
            testSetter(positive, lookup, c[0], c[1], testMode | TEST_NPE);
    }
    for (int isStaticN = 0; isStaticN <= 1; isStaticN++) {
        testSetter(false, lookup,
                   new Object[]{ (isStaticN != 0), System.class, "bogus", char.class },
                   null, testMode);
    }
}
 

@Test
public void testUserClassInSignature() throws Throwable {
    if (CAN_SKIP_WORKING)  return;
    startTest("testUserClassInSignature");
    Lookup lookup = MethodHandles.lookup();
    String name; MethodType mt; MethodHandle mh;
    Object[] args;

    // Try a static method.
    name = "userMethod";
    mt = MethodType.methodType(Example.class, Object.class, String.class, int.class);
    mh = lookup.findStatic(lookup.lookupClass(), name, mt);
    assertEquals(mt, mh.type());
    assertEquals(Example.class, mh.type().returnType());
    args = randomArgs(mh.type().parameterArray());
    mh.invokeWithArguments(args);
    assertCalled(name, args);

    // Try a virtual method.
    name = "v2";
    mt = MethodType.methodType(Object.class, Object.class, int.class);
    mh = lookup.findVirtual(Example.class, name, mt);
    assertEquals(mt, mh.type().dropParameterTypes(0,1));
    assertTrue(mh.type().parameterList().contains(Example.class));
    args = randomArgs(mh.type().parameterArray());
    mh.invokeWithArguments(args);
    assertCalled(name, args);
}
 

@Override
public Lookup apply(Class<?> clazz) {
    try {
        return (Lookup) privateLookupInMethod.invoke(null, clazz, MethodHandles.lookup());
    } catch (IllegalAccessException | InvocationTargetException e) {
        throw new IllegalStateException("Unable to get lookup for " + clazz.getName(), e);
    }
}
 

void testBind(boolean positive, Lookup lookup, Class<?> defc, Class<?> ret, String name, Class<?>... params) throws Throwable {
    countTest(positive);
    String methodName = name.substring(1 + name.indexOf('/'));  // foo/bar => foo
    MethodType type = MethodType.methodType(ret, params);
    Object receiver = randomArg(defc);
    MethodHandle target = null;
    Exception noAccess = null;
    try {
        if (verbosity >= 4)  System.out.println("lookup via "+lookup+" of "+defc+" "+name+type);
        target = maybeMoveIn(lookup, defc).bind(receiver, methodName, type);
    } catch (ReflectiveOperationException ex) {
        noAccess = ex;
        assertExceptionClass(
            (name.contains("bogus") || INIT_REF_CAUSES_NSME && name.contains("<init>"))
            ?   NoSuchMethodException.class
            :   IllegalAccessException.class,
            noAccess);
        if (verbosity >= 5)  ex.printStackTrace(System.out);
    }
    if (verbosity >= 3)
        System.out.println("bind "+receiver+"."+name+"/"+type+" => "+target
                +(noAccess == null ? "" : " !! "+noAccess));
    if (positive && noAccess != null)  throw noAccess;
    assertEquals(positive ? "positive test" : "negative test erroneously passed", positive, target != null);
    if (!positive)  return; // negative test failed as expected
    assertEquals(type, target.type());
    Object[] args = randomArgs(params);
    printCalled(target, name, args);
    target.invokeWithArguments(args);
    Object[] argsWithReceiver = cat(array(Object[].class, receiver), args);
    assertCalled(name, argsWithReceiver);
    if (verbosity >= 1)
        System.out.print(':');
}
 

void testFindConstructor(boolean positive, Lookup lookup,
                         Class<?> defc, Class<?>... params) throws Throwable {
    countTest(positive);
    MethodType type = MethodType.methodType(void.class, params);
    MethodHandle target = null;
    Exception noAccess = null;
    try {
        if (verbosity >= 4)  System.out.println("lookup via "+lookup+" of "+defc+" <init>"+type);
        target = lookup.findConstructor(defc, type);
    } catch (ReflectiveOperationException ex) {
        noAccess = ex;
        assertTrue(noAccess.getClass().getName(), noAccess instanceof IllegalAccessException);
    }
    if (verbosity >= 3)
        System.out.println("findConstructor "+defc.getName()+".<init>/"+type+" => "+target
                           +(target == null ? "" : target.type())
                           +(noAccess == null ? "" : " !! "+noAccess));
    if (positive && noAccess != null)  throw noAccess;
    assertEquals(positive ? "positive test" : "negative test erroneously passed", positive, target != null);
    if (!positive)  return; // negative test failed as expected
    assertEquals(type.changeReturnType(defc), target.type());
    Object[] args = randomArgs(params);
    printCalled(target, defc.getSimpleName(), args);
    Object obj = target.invokeWithArguments(args);
    if (!(defc == Example.class && params.length < 2))
        assertCalled(defc.getSimpleName()+".<init>", args);
    assertTrue("instance of "+defc.getName(), defc.isInstance(obj));
}
 

void testFindStatic(boolean positive, Lookup lookup, Class<?> defc, Class<?> ret, String name, Class<?>... params) throws Throwable {
    countTest(positive);
    String methodName = name.substring(1 + name.indexOf('/'));  // foo/bar => foo
    MethodType type = MethodType.methodType(ret, params);
    MethodHandle target = null;
    Exception noAccess = null;
    try {
        if (verbosity >= 4)  System.out.println("lookup via "+lookup+" of "+defc+" "+name+type);
        target = maybeMoveIn(lookup, defc).findStatic(defc, methodName, type);
    } catch (ReflectiveOperationException ex) {
        noAccess = ex;
        assertExceptionClass(
            (name.contains("bogus") || INIT_REF_CAUSES_NSME && name.contains("<init>"))
            ?   NoSuchMethodException.class
            :   IllegalAccessException.class,
            noAccess);
        if (verbosity >= 5)  ex.printStackTrace(System.out);
    }
    if (verbosity >= 3)
        System.out.println("findStatic "+lookup+": "+defc.getName()+"."+name+"/"+type+" => "+target
                +(noAccess == null ? "" : " !! "+noAccess));
    if (positive && noAccess != null)  throw noAccess;
    assertEquals(positive ? "positive test" : "negative test erroneously passed", positive, target != null);
    if (!positive)  return; // negative test failed as expected
    assertEquals(type, target.type());
    assertNameStringContains(target, methodName);
    Object[] args = randomArgs(params);
    printCalled(target, name, args);
    target.invokeWithArguments(args);
    assertCalled(name, args);
    if (verbosity >= 1)
        System.out.print(':');
}
 

private void introspectFields(ArrayList<MarshalField> fieldList,
                              PodImport moduleImport,
                              Class<?> sourceClass)
{
  if (sourceClass == null || Object.class.equals(sourceClass)) {
    return;
  }
  
  introspectFields(fieldList, 
                   moduleImport,
                   sourceClass.getSuperclass());
  
  Lookup lookup = MethodHandles.lookup();
  
  for (Field sourceField : sourceClass.getDeclaredFields()) {
    if (Modifier.isStatic(sourceField.getModifiers())) {
      continue;
    }
    
    try {
      sourceField.setAccessible(true);
      
      ModuleMarshal marshal;
      marshal = moduleImport.marshalArg(sourceField.getType(),
                                        Object.class);
      
      MethodHandle sourceHandle = lookup.unreflectGetter(sourceField);
      sourceHandle = sourceHandle.asType(MethodType.methodType(Object.class, Object.class));
    
      MarshalField fieldMarshal = new MarshalFieldObject(sourceField.getName(),
                                                         marshal, 
                                                         sourceHandle);
      
      fieldList.add(fieldMarshal);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}
 

@Override
public int hashCode() {
    final MethodHandles.Lookup lookup = getLookup();
    int h = lookup.lookupClass().hashCode() + 31 * lookup.lookupModes();
    final int c = getNameTokenCount();
    for(int i = 0; i < c; ++i) {
        h = h * 31 + getNameToken(i).hashCode();
    }
    return h * 31 + getMethodType().hashCode();
}
 

public void testRunnableProxy0() throws Throwable {
    if (CAN_SKIP_WORKING)  return;
    startTest("testRunnableProxy");
    MethodHandles.Lookup lookup = MethodHandles.lookup();
    MethodHandle run = lookup.findStatic(lookup.lookupClass(), "runForRunnable", MethodType.methodType(void.class));
    Runnable r = MethodHandleProxies.asInterfaceInstance(Runnable.class, run);
    testRunnableProxy(r);
    assertCalled("runForRunnable");
}
 

/**
 * The JVM is resolving a CONSTANT_MethodHandle CP entry.  And it wants our help.
 * It will make an up-call to this method.  (Do not change the name or signature.)
 * The type argument is a Class for field requests and a MethodType for non-fields.
 * <p>
 * Recent versions of the JVM may also pass a resolved MemberName for the type.
 * In that case, the name is ignored and may be null.
 */
static MethodHandle linkMethodHandleConstant(Class<?> callerClass, int refKind,
                                             Class<?> defc, String name, Object type) {
    try {
        Lookup lookup = IMPL_LOOKUP.in(callerClass);
        assert(refKindIsValid(refKind));
        return lookup.linkMethodHandleConstant((byte) refKind, defc, name, type);
    } catch (ReflectiveOperationException ex) {
        Error err = new IncompatibleClassChangeError();
        err.initCause(ex);
        throw err;
    }
}
 

void testFindConstructor(boolean positive, Lookup lookup,
                         Class<?> defc, Class<?>... params) throws Throwable {
    countTest(positive);
    MethodType type = MethodType.methodType(void.class, params);
    MethodHandle target = null;
    Exception noAccess = null;
    try {
        if (verbosity >= 4)  System.out.println("lookup via "+lookup+" of "+defc+" <init>"+type);
        target = lookup.findConstructor(defc, type);
    } catch (ReflectiveOperationException ex) {
        noAccess = ex;
        assertTrue(noAccess.getClass().getName(), noAccess instanceof IllegalAccessException);
    }
    if (verbosity >= 3)
        System.out.println("findConstructor "+defc.getName()+".<init>/"+type+" => "+target
                           +(target == null ? "" : target.type())
                           +(noAccess == null ? "" : " !! "+noAccess));
    if (positive && noAccess != null)  throw noAccess;
    assertEquals(positive ? "positive test" : "negative test erroneously passed", positive, target != null);
    if (!positive)  return; // negative test failed as expected
    assertEquals(type.changeReturnType(defc), target.type());
    Object[] args = randomArgs(params);
    printCalled(target, defc.getSimpleName(), args);
    Object obj = target.invokeWithArguments(args);
    if (!(defc == Example.class && params.length < 2))
        assertCalled(defc.getSimpleName()+".<init>", args);
    assertTrue("instance of "+defc.getName(), defc.isInstance(obj));
}
 

@Override
public int hashCode() {
    final MethodHandles.Lookup lookup = getLookup();
    int h = lookup.lookupClass().hashCode() + 31 * lookup.lookupModes();
    final int c = getNameTokenCount();
    for(int i = 0; i < c; ++i) {
        h = h * 31 + getNameToken(i).hashCode();
    }
    return h * 31 + getMethodType().hashCode();
}
 

private static boolean lookupsEqual(final Lookup l1, final Lookup l2) {
    if(l1 == l2) {
        return true;
    }
    if(l1.lookupClass() != l2.lookupClass()) {
        return false;
    }
    return l1.lookupModes() == l2.lookupModes();
}