To become a senior developer, you must master these core technologies of Java development

To master these core technologies of Java development and become an advanced developer, specific code examples are required

Java is a high-level programming language widely used in software development. As a Java developer, if you want to become a senior developer, in addition to mastering basic syntax knowledge, you also need to have an in-depth understanding and mastery of some core technologies. This article will introduce several important core Java development technologies and analyze them with specific code examples.

1. Multi-threaded programming

Multi-threaded programming is a core technology that cannot be ignored in Java development. In multi-threaded programming, we can execute multiple threads at the same time, thereby improving the concurrency and efficiency of the program. The following is a simple multi-threading sample code:

public class MultiThreadExample {
    public static void main(String[] args) {
        Thread thread1 = new Thread(new MyThread());
        Thread thread2 = new Thread(new MyThread());
        thread1.start();
        thread2.start();
    }
}

class MyThread implements Runnable {
    public void run() {
        for (int i = 0; i < 10; i++) {
            System.out.println(Thread.currentThread().getName() + " : " + i);
        }
    }
}

In the above code, we created a MyThread class and implemented the Runnable interface. In the run method, we define the execution logic of the thread. In the main thread, we create two thread objects and start these two threads through the start method.

Run the above code, you can see that two threads execute concurrently, and the output may be similar to the following:
Thread-0 : 0
Thread-1 : 0
Thread- 1 : 1
Thread-0 : 1
...

By learning multi-thread programming, we can improve the performance of the program with the help of concurrent execution of threads.

2. Collection Framework

The collection framework is a data structure widely used in Java development. It provides a series of collection classes for storing and manipulating data. Here is a sample code using an ArrayList collection:

import java.util.ArrayList;
import java.util.Iterator;

public class CollectionExample {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<String>();
        list.add("Java");
        list.add("Python");
        list.add("C++");
        
        Iterator<String> iterator = list.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }
    }
}

In the above code, we create an ArrayList object and add three string elements to it. When using an Iterator to traverse a collection, we can access the elements in the collection sequentially.

Run the above code, you will get the following output:
Java
Python
C

By learning the collection framework, we can flexibly manage and manipulate data.

3. IO stream operation

IO stream operation is a commonly used input and output method in Java development. Through IO streams, we can realize data exchange between programs and external files. The following is a simple file reading and writing sample code:

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class IOExample {
    public static void main(String[] args) {
        try {
            BufferedReader reader = new BufferedReader(new FileReader("input.txt"));
            BufferedWriter writer = new BufferedWriter(new FileWriter("output.txt"));

            String line;
            while ((line = reader.readLine()) != null) {
                writer.write(line);
                writer.newLine();
            }

            reader.close();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In the above code, we use BufferedReader and BufferedWriter to read and write files. By reading the file contents, we can write the data into another file.

By learning IO stream operations, we can better interact with data from external files.

Summary:

In this article, we introduced the three core technologies of Java development: multi-threaded programming, collection framework and IO stream operations. At the same time, we also provide specific code examples to help readers better understand these core technologies. By learning and mastering these technologies, I believe you can become an excellent senior Java developer.

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