Java access bean methods with LambdaMetafactory

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If you want to bind values to your lamba, you have to include these parameters to the invokedtype signature:

SimpleBean simpleBeanInstance = new SimpleBean();

MethodHandles.Lookup caller = MethodHandles.lookup();
MethodType getter=MethodType.methodType(Object.class);
MethodHandle target=caller.findVirtual(SimpleBean.class, "getObj", getter);
CallSite site = LambdaMetafactory.metafactory(caller,
    "get", // include types of the values to bind:
    MethodType.methodType(Supplier.class, SimpleBean.class),
    getter, target, getter);

MethodHandle factory = site.getTarget();
factory = factory.bindTo(simpleBeanInstance);
Supplier r = (Supplier) factory.invoke();
assertEquals( "myCustomObject", r.get());

Instead of binding a value you may use a Function which takes the bean as argument:

SimpleBean simpleBeanInstance = new SimpleBean();

MethodHandles.Lookup caller = MethodHandles.lookup();
MethodType getter=MethodType.methodType(Object.class);
MethodHandle target=caller.findVirtual(SimpleBean.class, "getObj", getter);
MethodType func=target.type();
CallSite site = LambdaMetafactory.metafactory(caller,
    "apply",
    MethodType.methodType(Function.class),
    func.erase(), target, func);

MethodHandle factory = site.getTarget();
Function r = (Function)factory.invoke();
assertEquals( "myCustomObject", r.apply(simpleBeanInstance));

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