Common Mistakes Java Developers Make this is test

BufferedReader br = new BufferedReader(new FileReader("file.txt")); 
String line = br.readLine(); 
// No br.close() – this causes resource leaks!
  

try (BufferedReader br = new BufferedReader(new FileReader("file.txt"))) { 
    String line = br.readLine(); 
}  
  

String name = getName(); //could return null 
System.out.println(name.toUpperCase()); // NullPointerException
  

Optional name = getNameOptional(); 
name.ifPresent(n -> System.out.println(n.toUpperCase())); 
  

List list = new LinkedList<>(); 
// Doing frequent get(index) – slow with LinkedList 
  

public class Counter { 
    private int count = 0; 
 
    public void increment() { 
        count++; // Not thread-safe 
    } 
} 
  

private AtomicInteger count = new AtomicInteger(0); 
public void increment() { 
    count.incrementAndGet(); 
}