How do I convert string to char array?

By Wayan in Core API, Lang Package 0 Comment

Here we have a small class that convert a string literal into an array, a character array. To do this we can simply use String.toCharArray() method.

package org.kodejava.lang;

public class StringToArrayExample {
    public static void main(String[] args) {
        // We have a string literal that contains the tag line of this blog.
        String literal = "Kode Java - Learn Java by Examples";

        // Now we want to convert or divided it into a small array of char.
        // To do this we can simply used String.toCharArray() method. This
        // method splits the string into an array of characters.
        char[] temp = literal.toCharArray();

        // Here we just iterate the char array and print it to our console.
        for (char c : temp) {
            System.out.print(c);
        }
    }
}

How do I get user home directory name?

By Wayan in Core API, Lang Package 0 Comment 
package org.kodejava.lang;

public class UserHomeExample {
    public static void main(String[] args) {
        // This is the key that we used to obtain user home directory
        // in the operating system
        String userHome = "user.home";

        // We get the path by getting the system property with the 
        // defined key above.
        String path = System.getProperty(userHome);

        // We print your home path here
        System.out.println("Your Home Path: " + path);
    }
}

On my machine it print something like:

Your Home Path: C:\Users\wsaryada

Or

Your Home Path: /Users/wsaryada

How do I get operating system name and version?

By Wayan in Core API, Lang Package 0 Comment 
package org.kodejava.lang;

public class OperatingSystemInfo {
    public static void main(String[] args) {
        // The key for getting operating system name
        String name = "os.name";
        // The key for getting operating system version
        String version = "os.version";
        // The key for getting operating system architecture
        String architecture = "os.arch";

        System.out.println("Name   : " + System.getProperty(name));
        System.out.println("Version: " + System.getProperty(version));
        System.out.println("Arch   : " + System.getProperty(architecture));
    }
}

Below is the example result of our program, of course it could be different from what you’ll see in your machine because it depends on the operating system that you use.

Name   : Windows 10
Version: 10.0
Arch   : amd64

Or

Name   : Mac OS X
Version: 10.12.6
Arch   : x86_64

How do I add a delay in my program?

By Wayan in Core API, Lang Package 0 Comment

You have a problem that you want to add a delay for a couple of seconds in your program. Using Thread.sleep() method we can add delay in our application in a millisecond time. The Thread.sleep() need to be executed inside a try-catch block, and we need to catch the InterruptedException. Let’s see the code snippet below.

package org.kodejava.lang;

public class DelayExample {
    public static void main(String[] args) {
        // This program demonstrate how to add a delay in our 
        // application.
        for (int i = 0; i < 10; i++) {
            // Print the value of i
            System.out.println("i = " + i);

            try {
                // Using Thread.sleep() we can add delay in our 
                // application in a millisecond time. For the example 
                // below the program will take a deep breath for one 
                // second before continue to print the next value of 
                // the loop.
                Thread.sleep(1000);

                // The Thread.sleep() need to be executed inside a 
                // try-catch block and we need to catch the 
                // InterruptedException.
            } catch (InterruptedException ie) {
                ie.printStackTrace();
            }
        }
    }
}

How do I get a part or a substring of a string?

By Wayan in Core API, Lang Package 0 Comment

The following code snippet demonstrates how to get some part from a string. To do this we use the String.substring() method. The first substring() method take a single parameter, beginIndex, the index where substring start. This method will return part of string from the beginning index to the end of the string.

The second method, substring(int beginIndex, int endIndex), takes the beginning index, and the end index of the substring operation. The index of this substring() method is a zero-based index, this means that the first character in a string start at index 0.

package org.kodejava.lang;

public class SubstringExample {
    public static void main(String[] args) {
        // This program demonstrates how we can take some part of a string 
        // or what we called as substring. Java String class provides 
        // substring method with some overloaded parameter.
        String sentence = "The quick brown fox jumps over the lazy dog";

        // The first substring method with single parameter beginIndex 
        // will take some part of the string from the beginning index 
        // until the last character in the string.
        String part = sentence.substring(4);
        System.out.println("Part of sentence: " + part);

        // The second substring method take two parameters, beginIndex 
        // and endIndex. This method returns the substring start from 
        // beginIndex to the endIndex.
        part = sentence.substring(16, 30);
        System.out.println("Part of sentence: " + part);
    }
}

This code snippet print out the following result:

Part of sentence: quick brown fox jumps over the lazy dog
Part of sentence: fox jumps over