Question

How can i check whether a package like javax.servlet.* exists or not in my installation of java?

Answer 1

Java can only tell you if it can load a class. It can’t tell you if a package exists or not because packages aren’t loaded, only classes.

The only way would be by trying to load a class from that package. e.g., For javax.servlet.* you could do:

try {
    Class.forName("javax.servlet.Filter");
    return true;
} catch(ClassNotFoundException e) {
    return false;
}