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Most people do not understand the knowledge points of this article "java how to rewrite findClass method", so the editor summarizes the following content, detailed content, clear steps, and has a certain reference value. I hope you can get something after reading this article. Let's take a look at this "java how to rewrite findClass method" article.

Method description

1. Using the findClass (String) method, you can reload the class bytecode file, because in ClassLoader, the ffindClass method is modified by protected, only quilt subclasses can be called, no method is implemented, and only an exception of ClassNotFoundException is thrown.

2. Rewrite the method of findClass so that it can be called by external objects and class the logic code of the bytecode file.

Example

Package com;import java.io.InputStream;import java.net.URL Public class MyClassLoader extends ClassLoader {/ * load class file * the purpose of rewriting this method is to allow this method to be called externally, and the findClass of the parent class is modified by protected Example of a full class name that can only be called by a subclass: com.xd.User * @ return * @ throws ClassNotFoundException * / @ Override public Class findClass (String name) throws ClassNotFoundException {try {/ / get the class file name remove the package path String fileName = name.substring (name.lastIndexOf (".") + 1) + ".class" / / get the file input stream InputStream is = this.getClass () .getResourceAsStream (fileName); / / read the byte byte [] b = new byte [is.available ()]; is.read (b); / / parse the byte byte stream into a Class object return defineClass (name, b, 0, b.length) that jvm can recognize } catch (Exception e) {throw new ClassNotFoundException ();} the above is about "how to rewrite the findClass method by java". I believe everyone has a certain understanding. I hope the content shared by the editor will be helpful to you. If you want to know more about the relevant knowledge, please follow the industry information channel.

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