Write to a config file

//Writing values to the config file

File configFile = new File("config.properties");

 

try {

    Properties props = new Properties();

    props.setProperty("host", "www.codejava.net");

    FileWriter writer = new FileWriter(configFile);

    props.store(writer, "host settings");

    writer.close();

} catch (FileNotFoundException ex) {

    // file does not exist

} catch (IOException ex) {

    // I/O error

}



















//Reading values from the config file

File configFile = new File("config.properties");

 

try {

    FileReader reader = new FileReader(configFile);

    Properties props = new Properties();

    props.load(reader);

 

    String host = props.getProperty("host");

 

    System.out.print("Host name is: " + host);

    reader.close();

} catch (FileNotFoundException ex) {

    // file does not exist

} catch (IOException ex) {

    // I/O error

}

SPRING BOOT: Complete Gold Mine!

Starting from controller to JPA using Spring Data! Why didn't I find this video before!!??

JAVA: Collections Framework at a glance!

JAVA MULTITHREADING: Producer-Consumer Pattern

So, imagine that we have a buffer.

The buffer can hold 10 items at once & is thread-safe in nature.

Now, a producer() method constantly populates it, another method called consumer() pulls one value out of it, every 1 second in average.

The code below is pretty interesting as this will cause both the threads to run and halt, synchronously, depending upon the state of 'queue' object.

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import java.util.Random; import java.util.concurrent.ArrayBlockingQueue; import java.util.concurrent.BlockingQueue; public class App{ //This is like a buffer which can hold 10 objects; here 10 integers //This is a thread-safe data-structure private static BlockingQueue<Integer> queue = new ArrayBlockingQueue<>(10); //Main method where 2 threads are run //1st method runs producer() method //2nd method runs consumer() method public static void main(String[] args) throws InterruptedException { Thread t1 = new Thread(new Runnable(){//<--To run producer() method @Override public void run() { try { producer(); } catch (InterruptedException e) { e.printStackTrace(); } } }); Thread t2 = new Thread(new Runnable(){//<--To run consumer() method @Override public void run() { try { consumer(); } catch (InterruptedException e) { e.printStackTrace(); } } }); t1.start(); t2.start(); t1.join(); t2.join();//<--Actually, only one join() is enough here. System.out.println("Program ended!"); } private static void producer() throws InterruptedException{ Random random = new Random(); while(true){//<--This run infinitely, to keep the queue full at all times queue.put(random.nextInt(100));//<--Generates integers within 100 } } private static void consumer() throws InterruptedException{ Random random = new Random(); while(true){ Thread.sleep(100);//<--Guarantees thread sleeping for 0.1s if(random.nextInt(10) == 0){//<--Generates a zero in 1 second statistically Integer value = queue.take(); System.out.println("Taken value: " + value + "; Queue size: " + queue.size()); } } } }