Learning Java Lambdas

Converting a method signature

Let's take the following method signature and turn it into a method descriptor:

long f (int n, String s, int[] array);

The method returns a long, so we describe the fact that it is a method with brackets and that it returns a long with a uppercase J.

()J

The first argument is of type int, so we use an uppercase I.

(I)J

The next argument is an object, so we use L to describe it's an object, fully qualify the name and close it with a semi-colon.

(ILString;)J

The last argument is an integer array so we drop in the array syntax followed by int type:

(ILString;[I)J

and we're done. A JVM method descriptor.