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Closure..

Couple of months back, when I started looking at Scala as a programming language, a key computer programming concept came up - Closure. I couldn't find a page which explains what it is and how to use it, so here it goes,

Definition

A closure is a first-class function with free variables that are bound in the lexical environment. (Source wikipedia)

First-class functions

First-class functions are those that can be assigned to a variable to be carried around and be executed at a later point of time. Subsequently this will enable those functions being passed as arguments, as well as returned back. An example in Scala is shown below.

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import java.util.WeakHashMap;

import junit.framework.Assert;

import org.junit.Test;

public class MemoryLeakTest {

	@Test
	public void test_stack_memory_leak() {

anoopelias

ObjMaker = function() {
	this.a = "first";
};

ObjMaker.prototype.b = "second";

var objMaker = new ObjMaker();
ObjMaker.prototype.c = "third";
console.log("objMaker.a " + objMaker.a); // Prints 'first'
console.log("objMaker.b " + objMaker.b); // Prints 'second'