What criteria must be met when creating classes used for resource initialization?

When creating classes for resource initialization in Java, it is important to adhere to the following criteria:

• Proper resource management: the class should guarantee the allocation and release of resources (e.g., file descriptors, database connections).
• Implementation of the AutoCloseable or Closeable interface: so that the try-with-resources construct can be used for automatic resource closing.
• Exception handling: proper handling of errors during resource initialization and release to prevent leaks.
• Idempotency of close(): the close() method should be safe to call multiple times without errors.

Example of a resource management class:

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

public class ResourceHandler implements AutoCloseable {
    private BufferedReader reader;

    public ResourceHandler(String filePath) throws IOException {
        reader = new BufferedReader(new FileReader(filePath));
    }

    public String readLine() throws IOException {
        return reader.readLine();
    }

    @Override
    public void close() throws IOException {
        if (reader != null) {
            reader.close();
        }
    }
}

This approach ensures reliable and safe resource usage.