java Archives

Displaying directory contents in Java

February 17, 2023February 2, 2023 by Manish Sahu

For listing a directory content in java we use File class and use isDirectory() method to check whether it is directory or not. if directory then we use listFiles().

package io;


import java.io.File;

public class DirProperties {

    public static void main(String[] args) {
        File f = new File("D:\\ebhor");
        if (f.exists() == false) {
            System.out.println("File  or Directory does not exists");
            if (f.mkdir()) {
                System.out.println("File is created");
            }
        }
        if (f.isDirectory()) {
            System.out.println("This is a directory");
        }
        System.out.println("Total space is " + f.getTotalSpace());
        File[] f1 = f.listFiles();
        for (File ff : f1) {
            System.out.println(ff.toString());
        }
   }
}

package io;

import java.io.File;

public class DirProperties {

public static void main(String[] args) {

File f = new File("D:\\ebhor");

if (f.exists() == false) {

System.out.println("File or Directory does not exists");

if (f.mkdir()) {

System.out.println("File is created");

}

if (f.isDirectory()) {

System.out.println("This is a directory");

}

System.out.println("Total space is " + f.getTotalSpace());

File[] f1 = f.listFiles();

for (File ff : f1) {

System.out.println(ff.toString());

}

Converting given string to upper and lower case in Java

February 14, 2023February 2, 2023 by Manish Sahu

public class StringCaseChange {
    public static void main(String[] args)
    {
        String sentence="Welcome to Java World";
        String upperSentense=sentence.toUpperCase();
        System.out.println("Sentence in upper case : "+upperSentense);
        String lowerSentense=sentence.toLowerCase();
        System.out.println("Sentence in lower case : "+lowerSentense);
    }
 }

public class StringCaseChange {

public static void main(String[] args)

{

String sentence="Welcome to Java World";

String upperSentense=sentence.toUpperCase();

System.out.println("Sentence in upper case : "+upperSentense);

String lowerSentense=sentence.toLowerCase();

System.out.println("Sentence in lower case : "+lowerSentense);

}

toUpperCase() and toLowerCase() are methods in String class which converts given string in upper and lower case respectively and return a string.

Generating a random number between range in Java

March 2, 2023February 2, 2023 by manish

What is random number? A random number is a number that is generated without any predictability or pattern. It is a value that is chosen at random from a set or range of possible values. Random numbers are commonly used in computer programming for various purposes such as generating unique IDs, simulating random events, and … Read more

Write a java program to reverse a string

February 2, 2023February 2, 2023 by manish

We are discussing java program to reverse a string using following ways Java program to reverse a string using StringBuffer or StringBuilder class Java program to reverse a string using Loops(Iteration) Java program to reverse a string using StringBuffer or StringBuilder class import java.util.Scanner; public class ReverseString { public static void main(String[] args) { Scanner … Read more

Thread stop method in Java

February 4, 2023February 2, 2023 by manish

In java, stop() method kills/terminates the currently executing thread. class A extends Thread { public void run() { for (int i = 1; i

Thread Yield method in Java

February 4, 2023February 2, 2023 by manish

In java, yield() method temporarily pause the currently executing thread object and allow other threads to execute. class A extends Thread { public void run() { for (int i = 1; i

Reading a file using FileInputStream

March 2, 2023February 2, 2023 by Manish Sahu

Reading a file using FileInputStream To read a file using FileInputStream in Java, follow these steps: Import the necessary packages: import java.io.FileInputStream; import java.io.IOException; 2. Create a FileInputStream object for the file you want to read: FileInputStream fis = new FileInputStream(“filename.txt”); 3. Create a buffer array to store the data you read from the file: … Read more

Concatenating two strings in Java

February 2, 2023February 2, 2023 by Manish Sahu

public class StringConcate {

    public static void main(String[] args) {
        String s1 = "Welcome to";
        String s2 = " Java";
        String s3 = s1 + s2;
        System.out.println(s3);
        String s4 = s1.concat(s2);
        System.out.println(s4);
    }
}

public class StringConcate {

public static void main(String[] args) {

String s1 = "Welcome to";

String s2 = " Java";

String s3 = s1 + s2;

System.out.println(s3);

String s4 = s1.concat(s2);

System.out.println(s4);

}

The + operator can be used for concatenation of strings. concat(String str) is a method of String class that concatenate two strings and return a String.

Basics of Applet in Java

February 4, 2023February 2, 2023 by manish

The Java Applet is a special Java program that are primarily used in a internet programming. Applet program runs on a web browser at client side. Applet program are used to make the web site more dynamic. Applet program embedded in a HTML page and hosted on a web server. Applet Skeleton/ Structure Applet skeleton … Read more

indexof and lastindexof Java Examples

February 1, 2023February 1, 2023 by Manish Sahu

public class StringIndexOf {

    public static void main(String[] args) {
        String sentence = "This is a ball. its color is black";
        System.out.println("first index of \"l\" is " + sentence.indexOf('l'));
        System.out.println("first index of \"l\" after position 15 is " + sentence.indexOf('l', 15));
        int i = sentence.lastIndexOf('l');
        System.out.println("last index of \"l\" is " + i);
        System.out.println("last index of \"l\" is " + sentence.lastIndexOf('l',23));
     }
}

public class StringIndexOf {

public static void main(String[] args) {

String sentence = "This is a ball. its color is black";

System.out.println("first index of \"l\" is " + sentence.indexOf('l'));

System.out.println("first index of \"l\" after position 15 is " + sentence.indexOf('l', 15));

int i = sentence.lastIndexOf('l');

System.out.println("last index of \"l\" is " + i);

System.out.println("last index of \"l\" is " + sentence.lastIndexOf('l',23));

}

indexOf(int ch) returns int value that is the first occurrence of specified character in given string. Counting start from 0. If character not found it returns -1 indexOf(int ch, int fromIndex) returns int value that is the first occurrence of specified character in given string after specified position. If character not found it returns … Read more