JPF is a model checking tool for Java applications. It is a Virtual Machine (VM) for Java bytecode which executes the system under test (SUT). The JPF source is partially compatible with Java 11. The problem is to support new features of Java 11 like the bootstrap methods. They are used for things as common as string concatenation ( String + String, String + int, String + double, String + Byte, etc ). As of now, a few specialized cases are supported, but there are still few cases that fail with Java 11. There are also some internal APIs from Java 11 that no longer exist in Java 12. Therefore the aim of this project is to support the general case of bootstrap methods and update the code to support java 12.