When running Java programs, this version was compiled Java byte code with a particular. This creates a dependency, the Java version on the target system needed for that, right? As it is now possible at the start of the program to check whether the installed JRE requirements of the compiled version of Java meets the? And the one custom error message will appear if the execution fails because the version and not just a cryptic error message of the JRE. Even if no Java is installed, there is probably no way to verify this platform independent, right? Something like a small program, which with System.getProperty ("java.version") determines the current version, even with Java 1.0 (?) was compiled and a class loader for all of the following classes have / use? What do you think?