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 <K, V> 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

Answer 2

It is a generic method. The first is for the generic type that would be used. The function is also declaring that is returns that type T. The parameters are showing that they use that generic parameter type.