bytecode

问题 It seems that openJDK 8 places private methods which are not final nor static into vtable. Why is it so when dynamic binding is not used for private methods (since they're invoked with invokespecial) or is it used? 回答1: This is done to handle some rare situations when an overridable method with the same name and signature exists in a superclass. Though there is definitely a place for improvement, may be, targeted for JDK 9. See https://bugs.openjdk.java.net/browse/JDK-8024368 Private methods

问题 Lets say , there are some import statements in a class. When the byte code is generated for that class, what happens to these import statements. If the import statements are ignored during runtime, how are the dependencies on that classes methods resolved during runtime. 回答1: The purpose of import statements is just to make life easier for the human readers (and authors) of the code. Thus they are replaced by references to the fully qualified class/method names in the bytecode. And unused

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 2 years ago . When creating a proxy with for example cglib or javassist proxies, this proxy is implemented by creating a subclass of the proxy target. However, this means that the annotations on this proxy are lost. This is problematic when a class is processed by two libraries where: The first libraries requires the creation

问题 I would like to find the offsets of different methods in test cases I work with. I can find where methods start and end, I look for opcodes RETURN and ARETURN (Im doing so in a class that extends a methodVisitor in the method visitInsn()), but I have not been able to find the offset where those happen in the bytecode. Any ideas? Just in case: I am working with the core API of ASM, I am aware that the tree API could help me find what I need, but the tree API makes everything go slow and use

问题 I am making software that will need to dynamically create java bytecode, and possibly even make it a runnable jar. My current idea is to create a new .java file and compile it at runtime. I can create the file, but I'm not sure how to compile it at runtime, and make it a runnable jar. Any help would be greatly appreciated. public static String generate(String filePath) { try { File file = new File("Test.java"); if(!file.exists())file.createNewFile(); FileWriter write = new FileWriter(filePath

问题 I need a full bytecode-level execution trace of the entire Java program. I found the JVM TI with the SingleStep event which allosw me to WRITE an agent which will produce the trace. But surely there is a ready-made JVM option somewhere? 回答1: Use a debug build of the Hotspot JVM and run it with the -XX:+TraceBytecodes flag. See Trace java bytecode stream for how to build this debug JVM. 回答2: A full Java bytecode trace? That sounds incredibly slow. HotSpot does not support this functionality

问题 Say I have private void ThisIsMySecurityMethodPleaseLookHERE() { //security stuff } In my program, but that method is called nowhere in any of the actually executed code. Does it get compiled to bytecode? Or does the Java compiler recognize that fact and filter it out? I know it would never make it PAST bytecode, since it is not truly called. I ask because I know Java is notoriously easy to decompile. would all of my unused methods also be present when they decompile one of my .class files? I

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 5 years ago . The idea is to compare two jars and see if they were generated from same source and compare if they're identical at Binary/Byte code level. Also if they're both compiled with the same compiler i.e. Eclipse JDT or JIT etc compiler. I've looked at Apache Common BCEL, but it only does comparison after decomposing

问题 Goal Detecting where comparisons between and copies of variables are made Inject code near the line where the operation has happened The purpose of the code: everytime the class is ran make a counter increase General purpose: count the amount of comparisons and copies made after execution with certain parameters 2 options Note: I always have a .java file to begin with 1) Edit java file Find comparisons with regex and inject pieces of code near the line And then compile the class (My

问题 This is the code which I am trying out: JavaCompiler compilerA = ToolProvider.getSystemJavaCompiler(); int resultA = compilerA.run(null,null,null,"/Users/a/Documents/Java/a.java"); System.out.println("Compile result code = " + resultA); File fileA = new File("/Users/a/Documents/Java/a.class"); JavaCompiler compilerB = ToolProvider.getSystemJavaCompiler(); int resultB = compilerB.run(null,null,null,"/Users/a/Documents/Java/b.java"); System.out.println("Compile result code = " + resultB); File