Flow Java is a conservative extension to the Java programming language. It integrates single assignment variables and logic variables, to Java. Its development was influenced by Mozart/Oz. Conceptually, the extension is similar to adding immutable futures but goes beyond that by incorporating equivalence groups.

single

Syntactically, the extension adds few new tokens ...

single Object s;

...which introduces a single assignment variable, and...

s @= new Object();

...which binds s to a new object. Or...

Object o = new Object;

s @= o;

...which binds s to o. This makes s equivalent to o.

References