What does T mean when used as a method signature? Is it a return type?

Question

abstract public  T iterEdges(EdgeFun func, T accum);

This is for a multithreaded library for graphs. I am not asking for anything

Answer 1

T is a generic type. It allows generic type invocation when using the class in actual code.

You may have also seen in hash maps. Below is the legend for other parameters

E - Element (used extensively by the Java Collections Framework)
K - Key
N - Number
T - Type
V - Value
S,U,V etc. - 2nd, 3rd, 4th types

http://docs.oracle.com/javase/tutorial/java/generics/types.html