JAVA EXAMPLE PROGRAMS

JAVA EXAMPLE PROGRAMS

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Program: Write a program to implement ArrayList.


Description:
Write a program to implement your own ArrayList class. It should
contain add(), get(), remove(), size() methods. Use dynamic array logic.
It should increase its size when it reaches threshold.

Code:
package com.java2novice.algos;

import java.util.Arrays;

public class MyArrayList {

	private Object[] myStore;
	private int actSize = 0;
	
	public MyArrayList(){
		myStore = new Object[10];
	}
	
	public Object get(int index){
		if(index < actSize){
			return myStore[index];
		} else {
			throw new ArrayIndexOutOfBoundsException();
		}
	}
	
	public void add(Object obj){
		if(myStore.length-actSize <= 5){
			increaseListSize();
		}
		myStore[actSize++] = obj;
	}
	
	public Object remove(int index){
		if(index < actSize){
			Object obj = myStore[index];
			myStore[index] = null;
			int tmp = index;
			while(tmp < actSize){
				myStore[tmp] = myStore[tmp+1];
				myStore[tmp+1] = null;
				tmp++;
			}
			actSize--;
			return obj;
		} else {
			throw new ArrayIndexOutOfBoundsException();
		}
		
	}
	
	public int size(){
		return actSize;
	}
	
	private void increaseListSize(){
		myStore = Arrays.copyOf(myStore, myStore.length*2);
		System.out.println("\nNew length: "+myStore.length);
	}
	
	public static void main(String a[]){
		MyArrayList mal = new MyArrayList();
		mal.add(new Integer(2));
		mal.add(new Integer(5));
		mal.add(new Integer(1));
		mal.add(new Integer(23));
		mal.add(new Integer(14));
		for(int i=0;i<mal.size();i++){
			System.out.print(mal.get(i)+" ");
		}
		mal.add(new Integer(29));
		System.out.println("Element at Index 5:"+mal.get(5));
		System.out.println("List size: "+mal.size());
		System.out.println("Removing element at index 2: "+mal.remove(2));
		for(int i=0;i<mal.size();i++){
			System.out.print(mal.get(i)+" ");
		}
	}
}

Output:
2 5 1 23 14 
New length: 20
Element at Index 5:29
List size: 6
Removing element at index 2: 1
2 5 23 14 29 
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List Of All Interview Programs:

  1. How to reverse Singly Linked List?
  2. Find out duplicate number between 1 to N numbers.
  3. Find out middle index where sum of both ends are equal.
  4. Write a singleton class.
  5. Write a program to create deadlock between two threads.
  6. Write a program to reverse a string using recursive algorithm.
  7. Write a program to reverse a number.
  8. Write a program to convert decimal number to binary format.
  9. Write a program to find perfect number or not.
  10. Write a program to implement ArrayList.
  11. Write a program to find maximum repeated words from a file.
  12. Wrie a program to find out duplicate characters in a string.
  13. Write a program to find top two maximum numbers in a array.
  14. Write a program to sort a map by value.
  15. Write a program to find common elements between two arrays.
  16. How to swap two numbers without using temporary variable?
  17. Write a program to print fibonacci series.
  18. Write a program to find sum of each digit in the given number using recursion.
  19. Write a program to check the given number is a prime number or not?
  20. Write a program to find the given number is Armstrong number or not?
  21. Write a program to convert binary to decimal number.
  22. Write a program to check the given number is binary number or not?
  23. Write a program for Bubble Sort in java.
  24. Write a program for Insertion Sort in java.
  25. Write a program to implement hashcode and equals.
  26. How to get distinct elements from an array by avoiding duplicate elements?
  27. Write a program to get distinct word list from the given file.
  28. Write a program to get a line with max word count from the given file.
  29. Write a program to convert string to number without using Integer.parseInt() method.
  30. Write a program to find two lines with max characters in descending order.
  31. Write a program to find the sum of the first 1000 prime numbers.
  32. Find longest substring without repeating characters.
  33. Write a program to remove duplicates from sorted array.
  34. How to sort a Stack using a temporary Stack?
Knowledge Centre
Purpose of garbage collection
The garbage collection process is to identify the objects which are no longer referenced or needed by a program so that their resources can be reclaimed and reused. These identified objects will be discarded.
Famous Quotations
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
-- William Arthur Ward

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Reference: Java™ Platform Standard Ed. 7 - API Specification | Java is registered trademark of Oracle.
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