In this post we’ll have Java programs for displaying patterns which are the beginner level programs to understand and use loops in Java. In these Java programs outer and inner for loops are used to display patterns using numbers or symbols. Java program for pyramid pattern – Pattern 1 A…
In this post we’ll see how to write a Java program to arrange given non-negative numbers to form the biggest number. For example if there is an array of numbers {45, 3, 89, 123} then the numbers should be arranged as 89453123 to form the biggest number. If array of…
Write a Java program to find duplicate characters in a String with the repetition count is asked in many interviews. This post gives two ways to write a program for this problem. 1- You can use a HashMap to find duplicate characters in a String along with repetition count. 2-…
In this post we’ll see a Java program to reverse each word in a String individually rather than reversing the whole string. Steps to reverse each word in a String In order to write a Java program to reverse each word in a String you can follow the steps as…
In your Java program you may have a requirement to convert a char to String or to convert a String to char. This post shows different options to do these conversions. Convert char to String in Java For converting char to String in Java there is a toString() method in…
Some times you may need to list all the files in a directory to get a specific file, to read all the files or to zip a folder where you need to go through the whole folder tree structure. This post shows how you can list all the files and…
If you have to read input from console in Java there are 3 options. Using BufferedReader class. See example. Using Scanner class, available from Java 5. See example. Using System.console() method, available from Java 6. See example. Using BufferedReader class By wrapping the standard input stream “System.in” in an InputStreamReader…
When you zip a file in Java there are code changes based on whether you are zipping a file or you are zipping a folder in Java where the whole directory structure is archived. But unzipping a file in Java doesn’t need such different functionalities. One Java program to unzip…
In the post How to Zip Files in Java we have seen how to zip a single file or multiple files in Java but you may also need to zip a folder in Java where you also retain the folder tree structure while zipping it. This post shows how to…
This post shows how you can zip files in Java. Using the options given here you can zip a single file or more than one file by specifying all those files. Zip a file in Java To zip files in Java there are two options- Using ZipOutputStream and ZipEntry classes…