aload | Loads images , background images | Computer Vision library

Thanks @Barmar for your suggestions, I have finally implemented a working solution.

What does this typeSwitch() method do?

The invokeDynamic instruction (upon first being hit) calls the SwitchBootstraps.typeSwitch() method. This method then returns what method call should be executed (this is what invokedynamic generally does).

The last argument of the SwitchBootstraps.typeSwitch() method (the labels parameter) is in this case the list of classes in the switch: Number.class, Enum.class, String.class

The SwitchBootstraps.typeSwitch() bootstrap method checks the labels parameter for correctness and then returns a ConstantCallSite for the SwitchBootstraps.doTypeSwitch() method that does the effective handling (i.e. the final execution of the invokeDynamic instruction).

If you look at what SwitchBootstraps.doTypeSwitch() does: it iterates over the list of classes and returns the first found match.

What's the purpose of the additional int passed?

The additional parameter (startIndex) is needed because of this case:

Have your Agent listen to the creation of new ClassLoaders and then attach instances of them to the new ClassLoaders.

This way you preserve your "Agent listens to ClassLoader" interface, even if it now extends beyond the one platform class loader you expected the Agent to listen to.

To create a stack manipulation for a dynamic method invocation, instead of InvokeDynamic (a more high level Implementation), use

All Django forms are CSRF protected by default, and your HTML input element counts as a form. Either include the {% csrf_token %} tag in your HTML or include the @csrf_exempt decorator in your views.py file. See more docs here:

Django CSRF tokens

This is decompiled code, so the bytecode actually allocates and initialize those. int var6 = false; doesn't even compile.

This is not a direct answer, but I'm suggesting your decompiler just interprets wrong. Would make more sense to examine the bytecode rather than decompiled best effort guesses.

I've seen a lot of decompiled java code that doesn't make any sense, and that has been a problem of the decompilers used, not of the code.

Your logic of building a try-catch block is correct, except that you are using variables var + 1 to var + 3 which may clash with uses by the original code. When I try your code to instrument an example specifically chosen such that it has no such variable clashes, it works.

You could work-around such issues using a LocalVariablesSorter but it requires calls to newLocal to declare a variable for your injected code and since there’s no such call in your code, I assume, you’re not using LocalVariablesSorter.

Generally, injecting code of such complexity, even potentially multiple times, not only is error prone, it might raise the code size significantly, up to the point that it exceeds the maximum code size of a method.

The preferable approach is to move the complex code in a method on its own, which might even be delivered in precompiled form, i.e. created using ordinary Java source code, and only inject an invocation of that method.

So, assuming a helper class like

The problem is that you do Type.getInternalName(BuildingInfo.class). That's the very class you're trying to transform as it's being loaded, so you created a circular reference by using it in a way that would need it to be loaded. You'll need to hardcode the string "mcjty/lostcities/dimensions/world/lost/BuildingInfo" there instead.

Also, in "()Lmcjty/lostcities/api/ILostCityBuilding", that's supposed to have a semicolon at the end, so change it to "()Lmcjty/lostcities/api/ILostCityBuilding;".

Finally, you need to change false to true in new MethodInsnNode(INVOKEINTERFACE, Type.getInternalName(ILostCityBuilding.class), "getMinCellars", "()I", false));, since it is in fact an interface method.

Here's the problem: