How to Load Java Properties File Dynamically From the Classpath

Why this properties file ? if we are using any application where there is a chance of constantly changing any credentials, something consider any java email application or any there you may need to change from,to or any properties right ? In this situation what you have to do is, opening .java file and doing the modifications and again re-compile and re-deploy.  Think what if you need to change 100′s of .java files hmm so this .properties file.
We will place this .properties file in general at classpath location, will see how to load that properties file into .java programs and how to use it.

In this application my properties file name  = java4s.properties

ClientLogic.javva

package java4s; import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.util.Properties; public class ClientLogic { public static void main(String... args) { // First Way Properties prop = new Properties(); InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("java4s.properties"); try{ prop.load(inputStream); }catch(IOException e) { e.printStackTrace(); } System.out.println("------- By Using Thread class -------"); //Print required values System.out.println(prop.get("user")); //Print all the properties System.out.println(prop); // Second Way URL url = ClassLoader.getSystemResource("java4s.properties"); try{ prop.load(url.openStream()); }catch(Exception e) { e.printStackTrace(); } System.out.println("------- By Using URL class -------"); System.out.println(prop); } }

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package java4s;   import java.io.IOException; import java.io.InputStream; import java.net.URL; import java.util.Properties;   public class ClientLogic {       public static void main(String... args)     {   // First Way           Properties prop = new Properties();         InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("java4s.properties");           try{         prop.load(inputStream);         }catch(IOException e)         {             e.printStackTrace();         }           System.out.println("------- By Using Thread class -------");         //Print required values         System.out.println(prop.get("user"));           //Print all the properties         System.out.println(prop);   // Second Way           URL url = ClassLoader.getSystemResource("java4s.properties");         try{         prop.load(url.openStream());         }catch(Exception e)         {             e.printStackTrace();         }         System.out.println("------- By Using URL class -------");         System.out.println(prop);       } }