30 Pattern Programs In Java That You Should Learn In 2022

Introduction

For aspiring Java professionals, Java Pattern Programs are critical to understand and practice as the pattern-based Java programs help analyze programming ability. In this listicle, we have tried to provide pattern programs in Java with detailed explanations. This blog will be a comprehensive guide for how to print patterns in Java.

Contents at a glance:

1. Pyramid Pattern Programs in Java
2. Sandglass Java Star Pattern Program
3. Right Triangle Star Pattern Programs in Java
4. Left Triangle Star Pattern Programs in Java
5. Diamond Pattern Program in Java
6. Downward Triangle Star Pattern Program in Java
7. Mirrored Right Triangle Star Pattern Programs in Java
8. Reversed Pyramid Star Pattern Programs in Java
9. Right down Mirror Star Pattern Programs in Java
10. Diamond Number Pattern Programs in Java
11. Alphabet Pattern Programs in Java
12. Character Pattern Programs in Java
13. Square Pattern Programs in Java
14. Pattern Matching Pattern Programs in Java
15. String Pattern Programs in Java
16. Word Pattern Programs in Java
17. Odd Number Pattern Programs in Java
18. Pascal’s Triangle Pattern Programs in Java
19. Java Number Pattern Programs
20. Square Number Pattern Programs in Java
21. K Shape Alphabet Pattern Program
22. Triangle Character Pattern Program in Java
23. Diamond Pattern in Java
24. Down triangle star program
25. Alphabet A Pattern
26. Pattern Programs in Java
27. Zeroes & ones Pattern Programs
28. Binary Number Rectangle Pattern
29. Descending Numbers Pattern Program
30. Matrix Pattern programs in java

One of the most essential components of the Java Interview questions has always been Java Pattern Programs. Although they appear to be hard to solve at times, most often than not, they are just really based on mathematical logic and the principles of matrices.Therefore, pattern programs in java are always in high demand.
Patterns can be designed in a variety of creative, architectural, and behavioral ways to provide answers for instantiating an object in the best feasible way for specific conditions, depending on the pattern structure type.
When designing or changing applications or software programs, software designers employ Design Patterns as a prominent problem-solving strategy. It aids in the creation of simple, well-structured software that testers, developers, and users can understand and utilize.
Maintaining and introducing additional attributions in accordance with version requirements is simple; errors may be detected and promptly fixed if they occur. If necessary, developers can reuse programs; work on multiple interfaces and bridge them.

1. Pyramid Pattern Programs in Java

The pyramid is one of the simple pattern programs in Java that is often asked in interviews.

public class JigSawAcademy

{

public static void PyramidPattern(int n)

{

for (int i=0; i<n; i++) // for number of rows(n)

{ for (int j=n-i; j>1; j–) // a loop for spaces

{

System.out.print(” “); //to print space

}

for (int j=0; j<=i; j++ ) //for number of columns

{

System.out.print(“* “); //to print star

}

System.out.println(); //end-line after every row

}

}

public static void main(String args[]) //driver function,

{

int n = 5;

PyramidPattern(n);

}

}

Output:

*

* *

* * *

* * * *

* * * * *

It is one of the easiest pattern printing programs in Java.

2. Sandglass Java Star Pattern Program

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

System.out.println(“Enter the number of rows: “);

int rows = sc.nextInt();

for (int i= 0; i<= rows-1 ; i++)

{

for (int j=0; j <i; j++)

{

System.out.print(” “);

}

for (int k=i; k<=rows-1; k++) { System.out.print(“*” + ” “); } System.out.println(“”); } for (int i= rows-1; i>= 0; i–)

{

for (int j=0; j< i ;j++)

{

System.out.print(” “);

}

for (int k=i; k<=rows-1; k++)

{

System.out.print(“*” + ” “);

}

System.out.println(“”);

}

sc.close();

}

}

Output:

* * * * *

* * * *

* * *

* *

*

*

* *

* * *

* * * *

* * * * *

3. Right Triangle Star Pattern Programs in Java

public class RightTrianglePattern

{

public static void main(String args[])

{

// the rows to print

int i, j, row=6;

//the outer loop for rows

for(i=0; i<row; i++)

{

//the inner loop for columns

for(j=0; j<=i; j++)

{

//to prints stars

System.out.print(“* “);

}

// print new line

System.out.println();

}

}

}

Output:

*

* *

* * *

* * * *

* * * * *

4. Left Triangle Star Pattern Programs in Java

public class JigSawAcademy

{

public static void printStars(int n)

{

int i, j;

for(i=0; i<n; i++) //an outer loop for number of rows(n)

{ for(j=2*(n-i); j>=0; j–) // an inner loop for spaces

{

System.out.print(” “); // to print space

}

for(j=0; j<=i; j++) // an inner loop for columns

{

System.out.print(“* “); // to print star

}

System.out.println(); // end-line after every row

}

}

public static void main(String args[])

{

int n = 5;

printStars(n);

}

}

Output:

*

* *

* * *

* * * *

* * * * *

5. Diamond Pattern Program in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String args[])

{

int n, i, j, space = 1;

System.out.print(“Enter the number of rows: “);

Scanner s = new Scanner(System.in);

n = s.nextInt();

space = n – 1;

for (j = 1; j<= n; j++)

{

for (i = 1; i<= space; i++)

{

System.out.print(” “);

}

space–;

for (i = 1; i <= 2 * j – 1; i++)

{

System.out.print(“*”);

}

System.out.println(“”);

}

space = 1;

for (j = 1; j<= n – 1; j++)

{

for (i = 1; i<= space; i++)

{

System.out.print(” “);

}

space++;

for (i = 1; i<= 2 * (n – j) – 1; i++)

{

System.out.print(“*”);

}

System.out.println(“”);

}

}

}

Output:

*

***

*****

*******

*********

*******

*****

***

*

6. Downward Triangle Star Pattern Program in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

System.out.println(“Enter the number of rows: “); //to take input from user

int rows = sc.nextInt();

for (int i= rows-1; i>=0 ; i–)

{

for (int j=0; j<=i; j++)

{

System.out.print(“*” + ” “);

}

System.out.println();

}

sc.close();

}

}

Output:

* * * * *

* * * *

* * *

* *

*

7. Mirrored Right Triangle Star Pattern Programs in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

System.out.println(“Enter number of rows: “); // to take input from user

int rows = sc.nextInt();

for (int i= 0; i<= rows; i++)

{

for (int j=1; j<=rows-i; j++)

{

System.out.print(” “);

}

for (int k=0;k<=i;k++)

{

System.out.print(“*”);

}

System.out.println(“”);

}

sc.close();

}

}

Output:

*

**

***

****

*****

******

8. Reversed Pyramid Star Pattern Programs in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

System.out.println(“Enter the number of rows: “);

int rows = sc.nextInt();

for (int i= 0; i<= rows-1 ; i++)

{

for (int j=0; j<=i; j++)

{

System.out.print(” “);

}

for (int k=0; k<=rows-1-i; k++)

{

System.out.print(“*” + ” “);

}

System.out.println();

}

sc.close();

}

}

Output:

* * * * *

* * * *

* * *

* *

*

9. Right down Mirror Star Pattern Programs in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in); // to take input

System.out.println(“Enter number of rows: “);

int rows = sc.nextInt();

for (int i= rows; i>= 1; i–)

{

for (int j=rows; j>i;j–)

{

System.out.print(” “);

}

for (int k=1;k<=i;k++)

{

System.out.print(“*”);

}

System.out.println(“”);

}

sc.close();

}

}

Output:

*****

****

***

**

*

10. Diamond Number Pattern Programs in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args) {

for (int i = 1; i <= 4; i++)

{

int n = 4;

for (int j = 1; j<= n – i; j++) { System.out.print(” “); } for (int k = i; k >= 1; k–)

{

System.out.print(k);

}

for (int l = 2; l <= i; l++) { System.out.print(l); } System.out.println(); } for (int i = 3; i >= 1; i–)

{

int n = 3;

for (int j = 0; j<= n – i; j++) { System.out.print(” “); } for (int k = i; k >= 1; k–)

{

System.out.print(k);

}

for (int l = 2; l <= i; l++)

{

System.out.print(l);

}

System.out.println();

}

}

}

Output:

1

212

32123

4321234

32123

212

1

11. Alphabet Pattern Programs in Java

import java.util.Scanner;

public class JigSawAcademy

{

{

int alphabet = 65;

for (int i = 0; i <= 5; i++)

{

for (int j = 0; j <= i; j++)

{

System.out.print((char) (alphabet + j) + ” “);

}

System.out.println();

}

}

}

Output:

A

A B

A B C

A B C D

A B C D E

A B C D E F

12. Character Pattern Programs in Java

Character pattern programs in java using for loop prints the patterns in shapes of characters.

import java.util.Scanner;

public class JigSawAcademy

{public static void main(String[] args)

{

for (int i = 5; i >= 0; i–)

{

int alphabet = 65;

for (int j = 0; j <= i; j++)

{

System.out.print((char) (alphabet + j) + ” “);

}

System.out.println();

}

for (int i = 0; i<= 5; i++)

{

int alphabet = 65;

for (int j = 0; j <= i; j++)

{

System.out.print((char) (alphabet + j) + ” “);

}

System.out.println();

}

}

}

Output:

A B C D E F

A B C D E

A B C D

A B C

A B

A

A

A B

A B C

A B C D

A B C D E

A B C D E F

13. Square Pattern Programs in Java

import java.io.*;

class JigSawAcademy{

//print hollow rectangle

static void print_rectangle(int n, int m)

{

int i, j;

for (i = 1; i <= n; i++)

{

for (j = 1; j <= m; j++)

{

if (i == 1 || i == n ||

j == 1 || j == m)

System.out.print(“*”);

else

System.out.print(” “);

}

System.out.println();

}

}

//Driver program

public static void main(String args[])

{

int rows = 6, columns = 20;

print_rectangle(rows, columns);

}

}

Output:

********************

* *

* *

* *

* *

********************

14. Pattern Matching Pattern Programs in Java

public class REmatch {

public static void main(String[] argv) {

String patt = “Q[^u]\\d+\\.”;

Pattern r = Pattern.compile(patt);

String line = “Order QT300. Now!”;

Matcher m = r.matcher(line);

if (m.find()) {

System.out.println(patt + ” matches \”” +

m.group(0) +

“\” in \”” + line + “\””);

} else {

System.out.println(“NO MATCH”);

}

}

}

Output:

Q[\^u]\d+\. matches “QT300.” in “Order QT300. Now!”

15. String Pattern Programs in Java

package com.javainterviewpoint;

import java.util.Scanner;

public class Pattern24

{

public static void main(String[] args)

{

// to create a new Scanner object

Scanner scanner = new Scanner(System.in);

// to get the String from the user

System.out.println(“Enter the String which needs to be printed “);

String input = scanner.nextLine();

System.out.println(“** Printing the pattern… **”);

for (int i = 1; i <= input.length(); i++)

{

for (int j = input.length(); j > i; j–)

{

System.out.print(” “);

}

for (int k = i * 2 – 1; k >= 1; k–)

{

System.out.print(input.charAt(i – 1));

}

System.out.println(“”);

}

}

}

Output:

Enter the string which needs to be printed

JAVA

** Printing the pattern… **

J

AAA

VVVVV

AAAAAAA

16. Word Pattern Programs in Java

public boolean wordPattern(String pattern, String str) {

String[] arr = str.split(” “);

//to prevent out of boundary problem

if(arr.length != pattern.length())

return false;

HashMap<Character, String> map = new HashMap<Character, String>();

for(int i=0; i<pattern.length(); i++){

char c = pattern.charAt(i);

if(map.containsKey(c)){

String value = map.get(c);

if(!value.equals(arr[i])){

return false;

}

}else if (map.containsValue(arr[i])){

return false;

}

map.put(c, arr[i]);

}

return true;

}

17. Odd Number Pattern Programs in Java

import java.util.Scanner;

class Pattern {

static void display(int n)

{

int i, j, k;

for (i = 1; i <= n; i++) {

for (j = 1, k = i; j <= i; j++, k–) {

if (k % 2 == 0) {

// to display the numbers

System.out.print(j);

}

else {

//to display the stars

System.out.print(“*”);

}

}

System.out.print(“\n”);

}

}

// Driver Code

public static void main(String[] args)

{

// to get n

int n = 5;

// to print the pattern

display(n);

}

}

Output:

*

1

*

2

*

1*3*

*

2*4

18. Pascal’s Triangle Pattern Programs in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args) {

int n = 5;

for (int i = 0; i < n; i++) {

int number = 1;

System.out.printf(“%” + (n – i) * 2 + “s”, “”);

for (int j = 0; j <= i; j++) {

System.out.printf(“%4d”, number);

number = number * (i – j) / (j + 1);

}

System.out.println();

}

}

}

Output:

1

1 1

1 2 1

1 3 3 1

1 4 6 4 1

19. Java Number Pattern Programs

Pattern number programs in java print numbers in patterns like square, Damon, sandglass, and triangle.

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args) {

int i, j, k = 1;

for (i = 1; i <= 5; i++) {

for (j = 1; j< i + 1; j++) {

System.out.print(k++ + ” “);

}

System.out.println();

}

}

}

Output:

1

2 3

4 5 6

7 8 9 10

11 12 13 14 15

20. Square Number Pattern Programs in Java

import java.util.Scanner;

public class SquareNumber2 {

private static Scanner sc;

public static void main(String[] args)

{

int side, i = 0, j;

sc = new Scanner(System.in);

System.out.print(” Please Enter any Side of a Square : “);

side = sc.nextInt();

while(i < side)

{

j = 0;

while(j < side)

{

System.out.print(“1”);

j++;

}

i++;

System.out.print(“\n”);

}

}

}

Output:

1 2 3

1 2 3

1 2 3

Similarly, there are and that you can print in the same way.

21. K Shape Alphabet Pattern Program

import java.util.Scanner;

public class JigSawAcademy

{public static void main(String[] args)

{

for (int i = 5; i >= 0; i–)

{

int alphabet = 65;

for (int j = 0; j <= i; j++)

{

System.out.print((char) (alphabet + j) + ” “);

}

System.out.println();

}

for (int i = 0; i<= 5; i++)

{

int alphabet = 65;

for (int j = 0; j <= i; j++)

{

System.out.print((char) (alphabet + j) + ” “);

}

System.out.println();

}

}

}

A B C D E F

A B C D E

A B C D

A B C

A B

A

A

A B

A B C

A B C D

A B C D E

A B C D E F

22. Triangle Character Pattern Program in Java

public class JigSawAcademy

{

public static void main(String[] args)

{

for (int i = 0; i <= 5; i++) { int alphabet = 65; for (int j = 5; j > i; j–)

{

System.out.print(” “);

}

for (int k = 0; k <= i; k++)

{

System.out.print((char) (alphabet + k) + ” “);

}

System.out.println();

}

}

}

Output:

A

A B

A B C

A B C D

A B C D E

A B C D E F

23. Diamond Pattern in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args) {

char[] letter = { ‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’,

‘K’, ‘L’, ‘M’, ‘N’, ‘O’, ‘P’, ‘Q’, ‘R’, ‘S’, ‘T’, ‘U’, ‘V’,

‘W’, ‘X’, ‘Y’, ‘Z’ };

int letter_number = 0;

String[] diamond = new String[26]; // create an array of strings

System.out.print(“Enter any Character between A to Z : “);

Scanner reader = new Scanner(System.in);

try {

char user_letter = reader.next(“[A-Z]”).charAt(0);

// to search for letter number in the array letter

for (int i = 0; i < letter.length; i++) {

if (letter[i] == user_letter) {

letter_number = i;

break;

}

}

// to construct a diamond

for (int i = 0; i <= letter_number; i++) {

diamond[i] = “”;

// to add initial spaces

for (int j = 0; j < letter_number – i; j++) {

diamond[i] += ” “;

}

// to add letter

diamond[i] += letter[i];

// to add space between letters

if (letter[i] != ‘A’) {

for (int j = 0; j < 2 * i – 1; j++) { diamond[i] += ” “; } // to add letter diamond[i] += letter[i]; }

// to draw the first section of the diamond

System.out.println(diamond[i]); } for (int i = letter_number – 1; i >= 0; i–)

{

// to draw the second part of the diamond

// to write the diamondArray in reverse order

System.out.println(diamond[i]);

}

} catch (Exception e) {

e.printStackTrace();

} finally {

reader.close();

}

}

}

Output:

A

B B

C C

D D

E E

F F

E E

D D

C C

B B

A

24. Down triangle star program

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

System.out.println(“Enter the number of rows: “);

int rows = sc.nextInt();

for (int i=rows; i>= 1 ; i–)

{

for (int j = i; j < rows ; j++) {

System.out.print(” “);

}

for (int k = 1; k <= (2*i -1) ;k++) {

if( k==1 || i == rows || k==(2*i-1)) {

System.out.print(“*”);

}

else {

System.out.print(” “);

}

}

System.out.println(“”);

}

sc.close();

}

}

Output:

*********

* *

* *

* *

*

25. Alphabet A Pattern

import java.util.Scanner;

public class JigSawAcademy

{

// To print alphabet A pattern

void display(int n)

{

// an outer for loop for number of lines

for (int i = 0; i<=n; i++) {

// an inner for loop for logic execution

for (int j = 0; j<= n / 2; j++) {

// to print two column lines

if ((j == 0 || j == n / 2) && i != 0 ||

// to print first line of alphabet

i == 0 && j != n / 2 ||

// to print middle line

i == n / 2)

System.out.print(“*”);

else

System.out.print(” “);

}

System.out.println();

}

}

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

JigSawAcademy a = new JigSawAcademy();

a.display(7);

}

}

Output:

**

* *

***

* *

* *

* *

26. Pattern Programs in Java

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in); // rows value from the user

System.out.println(“Enter the number of rows: “);

int rows = sc.nextInt();

for (int i = 1; i <= rows; i++)

{

for (int j = 1; j <= i; j++)

{

System.out.print(i+” “);

}

System.out.println();

}

sc.close();

}

}

Output:

1

2 2

3 3 3

4 4 4 4

5 5 5 5 5

27. Zeroes & ones Pattern Programs

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

System.out.println(“Enter the number of rows: “);

int rows = sc.nextInt();

for (int i = 1; i <= rows; i++)

{

for (int j = 1; j <= i; j++)

{

if(j%2 == 0)

{

System.out.print(0);

}

else

{

System.out.print(1);

}

}

System.out.println();

}

sc.close();

}

}

Output:

1

10

101

1010

10101

28. Binary Number Rectangle Pattern

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

System.out.println(“Enter the number of rows: “);

int rows = sc.nextInt();

for (int i = 1; i <= rows; i++)

{

int num;

if(i%2 == 0)

{

num = 0;

for (int j = 1; j <= rows; j++)

{

System.out.print(num);

num = (num == 0)? 1 : 0;

}

}

else

{

num = 1;

for (int j = 1; j <= rows; j++)

{

System.out.print(num);

num = (num == 0)? 1 : 0;

}

}

System.out.println();

}

sc.close();

}

}

Output:

10101

01010

10101

01010

10101

29. Descending Numbers Pattern Program

import java.util.Scanner;

public class JigSawAcademy

{

public static void main(String[] args)

{

Scanner sc = new Scanner(System.in);

//take a row-value from the user

System.out.println(“How many rows do you want in this pattern?”);

int rows = sc.nextInt();

System.out.println(“Here is your pattern….!!!”);

for (int i = 1; i <= rows; i++)

{

for (int j = rows; j >= i; j–)

{

System.out.print(j+” “);

}

System.out.println();

}

//to close all the resources

sc.close();

}

}

Output:

7 6 5 4 3 2 1

7 6 5 4 3 2

7 6 5 4 3

7 6 5 4

7 6 5

7 6

7

30. Matrix Pattern programs in java

import java.io.*;

class JigSawAcademy

{

//to print the pattern

static void printPattern(int n)

{

// the number of rows & columns to print

int s = 2 * n – 1;

// upper half of matrix

for (int i = 0;

i < (s / 2) + 1; i++)

{

int m = n;

// the decreasing part

for (int j = 0; j < i; j++)

{

System.out.print(m + ” “);

m–;

}

// the constant part

for (int k = 0;

k < s – 2 * i; k++)

{

System.out.print(n – i + ” “);

}

// the increasing part.

m = n – i + 1;

for (int l = 0; l < i; l++)

{

System.out.print(m + ” “);

m++;

}

System.out.println();

}

// lower half of the matrix

for (int i = s / 2 – 1;

i >= 0; i–)

{

// the decreasing part

int m = n;

for (int j = 0; j < i; j++)

{

System.out.print(m + ” “);

m–;

}

// the constant part.

for (int k = 0;

k < s – 2 * i; k++)

{

System.out.print(n – i + ” “);

}

// the decreasing part

m = n – i + 1;

for (int l = 0; l < i; l++)

{

System.out.print(m + ” “);

m++;

}

System.out.println();

}

}

// the driver code

public static void main (String[] args)

{

int n = 3;

printPattern(n);

}

}

Output:

3 3 3 3 3

3 2 2 2 3

3 2 1 2 3

3 2 2 2 3

3 3 3 3 3

Conclusion

This blog is a collection of different pattern programs in java; From basic pattern programs in java to difficult pattern programs in java. If you wish to learn more about the various aspects of Java programming, check out our UNext page for other blogs regarding the same.

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