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Program: Write a program to implement ArrayList.

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.

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){
		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;
			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)+" ");

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
What is race condition?
A race condition is a situation in which two or more threads or processes are reading or writing some shared data, and the final result depends on the timing of how the threads are scheduled. Race conditions can lead to unpredictable results and subtle program bugs. A thread can prevent this from happening by locking an object. When an object is locked by one thread and another thread tries to call a synchronized method on the same object, the second thread will block until the object is unlocked.
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It’s not that I’m so smart, it’s just that I stay with problems longer.
-- Albert Einstein

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