Java 8 Functional Programming: Lazy Instantiation

Singletons often instantiate themselves lazily, and sometimes, if the object is heavy enough, class fields can be instantiated lazily. Generally, when going the lazy route, the getter method (or accessor) has to have a block of code that checks whether the object is instantiated yet (and, if it isn’t, it needs to be instantiated) before […]

from Java Code Geeks http://www.javacodegeeks.com/2015/01/java-8-functional-programming-lazy-instantiation.html