Java Type Inference in Generics

Type Inference in Generic

In Java 7, Type Inference is introduced in generics declaration which is used to reduce the coding as well to minimize the compile errors.

Made compiler smart enough to infer the type of generic instance. This is done by using "<>" operator and it is called as Diamond Operator. Not required to mention the type in between diamond operator and can be replaced declaring the type as left blank.

How to convert a String to an int in Java?

We will learn today, How to convert String to Int in java. This is very popular written test question in Java interviews.

For example, We have a String "12345" and now I want to represent it in integer.

We can do conversion in 4 ways.

1) Integer.parseInt method.
2) Integer.valueOf
3) Integer constructor
4) DecimalFormat class

Add ArrayList to another ArrayList in Java | addAll method

In this post, We will learn How to add ArrayList into a another ArrayList in java.

We can accumulate this in two ways.

1) While creating ArrayList object.
2) Using addAll method.

1) Adding existing ArrayList into new list:

ArrayList has a constructor which takes list as input. Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

ArrayList(Collection c)

Java API ArrayList Example

Java API ArrayList Overview

In this tutorial, We'll learn about Java Collection API ArrayList.
ArrayList is a class which is widely used in real time applications. It is in package java.util and public class. This is added in java 1.2 version.

Class Name: ArrayList
First Version: 1.2
Super Class: AbstractList
Implemented interfaces: List, RandomAccess, Cloneable, Serializable
Pacakge: java.util.