Posts Tagged With ‘java concept&8217


Sort a Map by its value

Below is a method which takes input as an unsorted map and returns a sorted one.
The task is accomplished by creating an anonymous java class.

For example: if original map is

{("sample1",58),("string3",34),("delta",85)}

The returned map would look like

{("delta",85),("sample1",58),("string3",34)}

public static > Map sortByValues(final Map map)
	{
		Comparator valueComparator = new Comparator() {
			public int compare(K k1, K k2)
				{
					int compare = map.get(k2).compareTo(map.get(k1));
					if (compare == 0)
						return 1;
					else return compare;
				}
		};
		Map sortedByValues = new TreeMap(valueComparator);
		sortedByValues.putAll(map);
		return sortedByValues;
	}

Let me know if you have a question.


Java Quick-facts

Java is an island in Indonesia to the south of Borneo; one of the world’s most densely populated regions.

However, we would focus here more on Java Programming language than the Island or the delicious coffee from that island.

Java is pioneer in Object Oriented Programming methodology.

Java treats every ‘object’ as an object in real world. Or, to put more clearly, mimic each and every process as close to real world. For example: air, wind are objects with peculiar property of their own.

As SCJP guide puts:

A Java program is mostly a collection of objects talking to other objects by invoking each other’s methods. Every object is of a certain type, and that type is defined by a class or an interface. Most Java programs use a collection of objects of many different types.

Class: A template that describes the kinds of state and behavior that objects of its type support.

Object: At runtime, when the Java Virtual Machine (JVM) encounters the new keyword, it will use the appropriate class to make an object which is an instance of that class. That object will have its own state, and access to all of the behaviors defined by its class.

State: (instance variables) Each object (instance of a class) will have its own unique set of instance variables as defined in the class. Collectively, the values assigned to an object’s instance variables make up the object’s state.

Behavior: (methods) When a programmer creates a class, she creates methods for that class. Methods are where the class’ logic is stored. Methods are where the real work gets done. They are where algorithms get executed, and data gets manipulated.