Java Program to convert ArrayList to String array

Posted by: Instanceofjava Posted date: February 05, 2018 / comment : 0 , ,

  • Java code to convert arraylist to string array.
  • We can convert ArrayList of strings to String array by using  toArray() method.
  • Lets see an Example java program to convert ArrayList to string array.



#1:  Java example program to convert ArrayList to String Array

  1. package com.instanceofjava;

  3. import java.util.ArrayList;
  4. import java.util.List;

  6. public class ArrayListToStringArray {
  7. /**
  8. * @author www.Instanceofjava.com
  9. * @category interview programs
  10. * 
  11. * Description: Java Prorgam to convert ArrayList to String array
  12. *
  13. */
  14. public static void main(String[] args) {
  16. List<String> lstflowers = new ArrayList<String>();
  17. lstflowers.add("Rose");
  18. lstflowers.add("Lilly");

  20. String[] arrayflower = new String[lstflowers.size()];
  21. arrayflower = lstflowers.toArray(arrayflower);

  23. for(String flower : arrayflower)
  24.     System.out.println(flower);
  25. }

  27. }


Output:


  1. Rose
  2. Lilly

#2:  Java example program to convert ArrayList to String Array Using java 8

  1. package com.instanceofjava;

  3. import java.util.ArrayList;
  4. import java.util.List;

  6. public class ArrayListToStringArray {
  7. /**
  8. * @author www.Instanceofjava.com
  9. * @category interview programs
  10. * 
  11. * Description: Java Prorgam to convert ArrayList to String array using java 8
  12. *
  13. */
  14. public static void main(String[] args) {
  16. List<String> lstflowers = new ArrayList<String>();
  17. lstflowers.add("Rose");
  18. lstflowers.add("Lilly");

  20. String[] arrayflower = lstflowers.toArray(new String[lstflowers.size()]);

  22. for(String flower : arrayflower)
  23.     System.out.println(flower);
  24. }

  26. }


java program to convert arraylist to string array

Java program to insert an element to ArrayList using ListIterator Example

Posted by: Instanceofjava Posted date: March 11, 2016 / comment : 1 , ,

1.Basic Java example program to insert element using list iterator to arraylist
  1. package com.javaIteratearraylistiterator;
  2.  
  3. import java.util.ArrayList;
  4. import java.util.Collections;
  5. import java.util.Iterator;
  6.  
  7. public class IterateListIteratorArrayList{
  8.  
  9. public static void main(String[] args) {
  10.   
  11. //create an ArrayList object
  12. ArrayList<String> arrayList = new ArrayList();
  13.        
  14. //Add elements to Arraylist
  15.  
  16. arrayList.add("A");
  17. arrayList.add("B");
  18. arrayList.add("C");
  19. arrayList.add("D");
  20. arrayList.add("F");
  21. arrayList.add("F");
  22. arrayList.add("G");
  23. arrayList.add("H");
  24. arrayList.add("I");
  25.     
  26.         
  27.  /*
  28. Get a ListIterator object for ArrayList using
  29. istIterator() method.
  30. */
  31.   
  32. System.out.println("Before inserting element");
  33.  
  34. for(int intIndex = 0; intIndex < arrayList.size(); intIndex++)
  35.               System.out.println(arrayList.get(intIndex)); 
  36. ListIterator itr = arrayList.listIterator();
  37.        
  38. /*
  39.       Use void add(Object o) method of ListIterator to add or insert an element
  40.       to List. It adds an element just before the element that would have
  41.       been returned by next method call and after the element that would have
  42.       returned by previous call.
  43.     */
  44.    
  45.     itr .next();
  46.        
  47.     //Add an element
  48.     itr .add("Added Element");
  49.     /*
  50.  
  51. System.out.println("After inserting element .");
  52.  
  53. for(int intIndex = 0; intIndex < arrayList.size(); intIndex++)
  54.               System.out.println(arrayList.get(intIndex));   
  55.  
  56. }
  57. }
     



Output:

  1. Before inserting element
  2. A
  3. B
  4. C
  5. D
  6. F
  7. F
  8. G
  9. H
  10. I
  11. After inserting element .
  12. A
  13. Added Element
  14. B
  15. C
  16. D
  17. F
  18. F
  19. G
  20. H
  21. I

How to Iterate ArrayList using Java ListIterator Example

Posted by: Instanceofjava Posted date: March 10, 2016 / comment : 0 ,

1.Basic Java example program to iterate arraylist elements using list iterator
  1. package com.javaIteratearraylistiterator;
  2.  
  3. import java.util.ArrayList;
  4. import java.util.Collections;
  5. import java.util.Iterator;
  6.  
  7. public class IterateListIteratorArrayList{
  8.  
  9. public static void main(String[] args) {
  10.   
  11. //create an ArrayList object
  12. ArrayList<String> arrayList = new ArrayList();
  13.        
  14. //Add elements to Arraylist
  15.  
  16. arrayList.add("A");
  17. arrayList.add("B");
  18. arrayList.add("C");
  19. arrayList.add("D");
  20. arrayList.add("F");
  21. arrayList.add("F");
  22. arrayList.add("G");
  23. arrayList.add("H");
  24. arrayList.add("I");
  25.     
  26.         
  27.  /*
  28. Get a ListIterator object for ArrayList using
  29. istIterator() method.
  30. */
  31.  
  32. ListIterator itr = arrayList.listIterator();
  33.        
  34. /*
  35. Use hasNext() and next() methods of ListIterator to iterate through
  36. the elements in forward direction.
  37. */
  38.  
  39. System.out.println("Iterating through ArrayList elements in forward  direction...");
  40.  
  41. while(itr.hasNext())
  42. System.out.println(itr.next());
  43.      
  44. /*Use hasPrevious() and previous() methods of ListIterator to iterate through
  45. the elements in backward direction.*/
  46.  
  47. System.out.println("Iterating through ArrayList elements in backward   direction...");
  48.         
  49.  
  50. while(itr.hasPrevious())
  51. System.out.println(itr.previous()); 
  52.   
  53. }
  54.  
  55. }
     



Output:

  1. Iterating through ArrayList elements in forward  direction...
  2. A
  3. B
  4. C
  5. D
  6. F
  7. F
  8. G
  9. H
  10. I
  11. Iterating through ArrayList elements in backward   direction...
  12. I
  13. H
  14. G
  15. F
  16. F
  17. D
  18. C
  19. B
  20. A

How to sort arraylist of strings alphabetically java

Posted by: Instanceofjava Posted date: March 10, 2016 / comment : 0 ,

1.Basic Java example program to sort arraylist of strings

  1. package com.javasortarraylistofobjects;
  2.  
  3. import java.util.ArrayList;
  4. import java.util.Collections;
  5. import java.util.Iterator;
  6.  
  7. public class SortArrayList{
  8.  
  9. public static void main(String[] args) {
  10.   
  11. //create an ArrayList object
  12. ArrayList<String> arrayList = new ArrayList();
  13.        
  14. //Add elements to Arraylist
  15.         
  16. arrayList.add("A"); 
  17. arrayList.add("C");
  18. arrayList.add("D");
  19. arrayList.add("Z");
  20. arrayList.add("F");
  21. arrayList.add("J");
  22. arrayList.add("K");
  23. arrayList.add("M");
  24. arrayList.add("L");
  25. arrayList.add("O");
  26.        
  27.         
  28.  System.out.println("Before sorting ArrayList ...");
  29.  Iterator itr=arrayList.iterator();
  30.         
  31. while (itr.hasNext()) {
  32.  
  33. System.out.println(itr.next());
  34.      
  35. }
  36.  
  37.        
  38.  /*
  39.  To sort an ArrayList object, use Collection.sort method. This is a
  40.   static method. It sorts an ArrayList object's elements into ascending order.
  41. */
  42.   Collections.sort(arrayList);
  43.      
  44.   System.out.println("After sorting ArrayList ...");
  45.        
  46.     
  47.         
  48. Iterator itr1=arrayList.iterator();
  49.         
  50. while (itr1.hasNext()) {

  52. System.out.println(itr1.next());
  53.             
  54. }
  55.     
  56.   
  57. }
  58. }
     




Output:

  1. Before sorting ArrayList ...
  2. A
  3. C
  4. D
  5. Z
  6. F
  7. J
  8. K
  9. M
  10. L
  11. O
  12. After sorting ArrayList ...
  13. A
  14. C
  15. D
  16. F
  17. J
  18. K
  19. L
  20. M
  21. O
  22. Z

Java Program to Sort elements of Java ArrayList Example

Posted by: Instanceofjava Posted date: March 10, 2016 / comment : 0 ,

1.Basic Java example program to sort arraylist of integers

  1. package com.javasortarraylistofobjects;
  2.  
  3. import java.util.ArrayList;
  4. import java.util.Collections;
  5. import java.util.Iterator;
  6.  
  7. public class SortArrayList{
  8.  
  9. public static void main(String[] args) {
  10.   
  11. //create an ArrayList object
  12.  ArrayList<Integer> arrayList = new ArrayList<Integer>();
  13.        
  14.  //Add elements to Arraylist
  15. arrayList.add(10);
  16. arrayList.add(7);
  17. arrayList.add(11);
  18. arrayList.add(4);
  19. arrayList.add(9);
  20. arrayList.add(6);
  21. arrayList.add(2);
  22. arrayList.add(8);
  23. arrayList.add(5);
  24. arrayList.add(1);
  25.         
  26.         
  27.  System.out.println("Before sorting ArrayList ...");
  28.  Iterator itr=arrayList.iterator();
  29.         
  30. while (itr.hasNext()) {
  31.  
  32. System.out.println(itr.next());
  33.      
  34. }
  35.  
  36.        
  37.  /*
  38.  To sort an ArrayList object, use Collection.sort method. This is a
  39.   static method. It sorts an ArrayList object's elements into ascending order.
  40. */
  41.   Collections.sort(arrayList);
  42.      
  43.   System.out.println("After sorting ArrayList ...");
  44.        
  45.     
  46.         
  47. Iterator itr1=arrayList.iterator();
  48.         
  49. while (itr1.hasNext()) {

  51. System.out.println(itr1.next());
  52.             
  53. }
  54.     
  55.   
  56. }
  57. }
     



Output:

  1. Before sorting ArrayList ...
  2. 10
  3. 7
  4. 11
  5. 4
  6. 9
  7. 6
  8. 2
  9. 8
  10. 5
  11. 1
  12. After sorting ArrayList ...
  13. 1
  14. 2
  15. 4
  16. 5
  17. 6
  18. 7
  19. 8
  20. 9
  21. 10
  22. 11

Basic Java example program to replace an element at specified index arraylist

Posted by: Instanceofjava Posted date: March 10, 2016 / comment : 0 ,

1.Basic java Example program to replace an element at specified index java arrayList.

  1. package com.instanceofjavaforus;
  2. import java.util.ArrayList;
  3.  
  4. public class ReplaceArrayList{
  5.  
  6. public static void main(String[] args) {
  7.   
  8. //create an ArrayList object
  9.  ArrayList<Integer> arrayList = new ArrayList<Integer>();
  10.        
  11.         //Add elements to Arraylist
  12.         arrayList.add(1);
  13.         arrayList.add(2);
  14.         arrayList.add(3);
  15.         arrayList.add(4);
  16.         arrayList.add(5);
  17.         arrayList.add(6);
  18.         arrayList.add(7);
  19.         arrayList.add(8);
  20.         arrayList.add(9);
  21.         arrayList.add(10);
  22.         
  23.  
  24.   /*
  25.   To replace an element at the specified index of ArrayList use
  26.   Object set(int index, Object obj) method.
  27.   This Object set(int index, Object obj) method replaces the specified element at the specified
  28.   index in the ArrayList and returns the element previously at the specified position.
  29.   */
  30.  
  31.  arrayList.set(1,23);
  32.      
  33.  System.out.println("ArrayList contains...");
  34.  Iterator itr=arrayList.iterator();
  35.  
  36. while (itr.hasNext()) {
  37.  
  38.  System.out.println(itr.next());
  39.  
  40.  }
  41.   
  42. }
  43. }
     



Output:

  1. ArrayList contains...
  2. 1
  3. 23
  4. 3
  5. 4
  6. 5
  7. 6
  8. 7
  9. 8
  10. 9
  11. 10

Search an element of Java ArrayList Example

Posted by: Instanceofjava Posted date: March 09, 2016 / comment : 0 ,

1.Basic java Example program to search an element  ArrayList.

  1. package com.instanceofjavaforus;
  2. import java.util.ArrayList;
  3.  
  4. public class SearchArrayList{
  5.  
  6. public static void main(String[] args) {
  7.   
  8. //create an ArrayList object
  9.  ArrayList<Integer> arrayList = new ArrayList<Integer>();
  10.        
  11.         //Add elements to Arraylist
  12.         arrayList.add(1);
  13.         arrayList.add(2);
  14.         arrayList.add(3);
  15.         arrayList.add(4);
  16.         arrayList.add(5);
  17.         arrayList.add(6);
  18.         arrayList.add(7);
  19.         arrayList.add(8);
  20.         arrayList.add(9);
  21.         arrayList.add(10);
  22.         
  23.  /*
  24.  To check whether the specified element exists in Java ArrayList use
  25. boolean contains(Object element) method.
  26. It returns true if the ArrayList contains the specified object, false
  27. otherwise.*/
  28.        
  29.         boolean isFound = arrayList.contains(2);
  30.         System.out.println("Does arrayList contain 2 ? " + isFound);
  31.      
  32.   /*
  33.    To get an index of specified element in ArrayList use
  34.    int indexOf(Object element) method.
  35.    This method returns the index of the specified element in ArrayList.
  36.    It returns -1 if not found.
  37.   */
  38.    
  39.    int index = arrayList.indexOf(11);
  40.  
  41.  if(index == -1)
  42.     System.out.println("ArrayList does not contain 11");
  43.   else
  44.     System.out.println("ArrayList contains 4 at index :" + index);
  45.         
  46.         
  47.    int secindex = arrayList.indexOf(5);
  48.  
  49.  if(secindex== -1)
  50.       System.out.println("ArrayList does not contain 5");
  51.  else
  52.      System.out.println("ArrayList contains 5 at index :" + secindex);
  53.        
  54.  System.out.println("Size of ArrayList: "+ arrayList.size()); 
  55.  
  56.  Iterator itr=arrayList.iterator();
  57.  
  58. while (itr.hasNext()) {
  59.  
  60.  System.out.println(itr.next());
  61.  
  62.  }
  63.   
  64. }
  65. }
     



Output:

  1. Does arrayList contain 2 ? true
  2. ArrayList does not contain 11
  3. ArrayList contains 5 at index :4
  4. Size of ArrayList: 10
  5. 1
  6. 2
  7. 3
  8. 4
  9. 5
  10. 6
  11. 7
  12. 8
  13. 9
  14. 10

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