How to make the jvm load my java.lang.String instead of the one in rt.jar

Question

I studied java classloader rencently. Now I want to write a class that has the same package name and class name as one of class in rt.jar. For example, write a java.lang.Str

Answer 1

You can do this using the -Xbootclasspath/p option at JVM startup:

-Xbootclasspath/p:/path/to/yourimpl.jar

/p stands for "prepend".

Note: -Xbootclasspath isn't a standard java option, so JVMs by different vendors may not support it.