bytecode

If you look at the byte code for Consumer<String> println = System.out::println; the byte code generates by Java 8 update 121 is GETSTATIC java/lang/System.out : Ljava/io/PrintStream; DUP INVOKEVIRTUAL java/lang/Object.getClass ()Ljava/lang/Class; POP INVOKEDYNAMIC accept(Ljava/io/PrintStream;)Ljava/util/function/Consumer; [ // handle kind 0x6 : INVOKESTATIC java/lang/invoke/LambdaMetafactory.metafactory(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodType;)Ljava/lang

Is there a utility (or eclipse plugin) for editing java class files ? I'd like to manipulate the bytecode of a java class file without recompiling it nor having a complete buildpath. E.g. to rename methods, add/delete instructions, change constants etc. The only utilities I found are: classeditor but it's very limited in functionality ( e.g. renaming of things and manipulating instructions isn't possible ). jbe doesn't save changes (maybe because class verifying fails - before I made any changes, although the class runs perfectly) (jbe initially had a classpath issue, adding the class path to

As a sort of follow up to the question called Differences between MSIL and Java bytecode? , what is the (major) differences or similarity in how the Java Virtual Machine works versus how the .NET Framework Common Language Runtime (CLR) works? Also, is the .NET framework CLR a "virtual machine" or does it not have the attributes of a virtual machine? benjismith There are a lot of similarities between both implementations (and in my opinion: yes, they're both "virtual machines"). For one thing, they're both stack-based VM's, with no notion of "registers" like we're used to seeing in a modern CPU

I was having a discussion about usage of String s and StringBuffer s in Java. How many objects are created in each of these two examples? Ex 1: String s = "a"; s = s + "b"; s = s + "c"; Ex 2: StringBuilder sb = new StringBuilder("a"); sb.append("b"); sb.append("c"); In my opinion, Ex 1 will create 5 and Ex 2 will create 4 objects. Alex Lockwood You can determine the answer by analyzing the java bytecode (use javap -c ). Example 1 creates two StringBuilder objects (see line #4) and two String objects (see line #7), while example 2 creates one StringBuilder object (see line #2). Note that you

I am really having trouble finding a good working Lua bytecode decompiler. I'm trying to decompile some scripting files I found in a game but they appear to be compiled, yet don't seem impossible to decode. What's the best tool to decompile Lua binaries? It looks like LuaDec itself was last updated for Lua 5.0.2. A new version targeting Lua 5.1.x bytecode has been released as LuaDec51 . The wiki is always a good place to start looking for resources as mentioned by f3lix. The mailing list is also a good place to ask. Do note that it is relatively easy to add obfuscation or even encryption to

What's a good free bytecode editor? I want an editor, something with a GUI... I tried jbe-0.1b with no luck (can't save the bytecode changes). Nothing decent with a UI, but you can use the Eclipse Bytecode Outline plugin to turn any Java class into ASM code, edit it, and produce the changed class. It's probably the most painless way at the moment. http://asm.ow2.org/eclipse/index.html I understand jasmin and jasper are the usual pair used to translate between bytecode and an assemly language representation. IIRC, Apache BCEL comes with a tool to disassemble class files to code which creates

I am writing an interpreter in Java for a domain-specific language with some scripting capabilities. I have already implemented a parser and now need to do a back end. To this end I am considering either to write my own interpreter (either working with abstract syntax trees or with some custom bytecodes) or target JVM (emit and execute Java bytecode at runtime). Could someone with more experience in this area say how feasible is the approach of targeting JVM and what libraries would you recommend to use for emitting Java bytecode? Here is a working "hello world" made with ObjectWeb ASM (a