What is the Difference Between Java 8 and Java 11?

Java 11 is an LTS (Long-Term Support) version released in September 2018, while Java 8 (released March 2014) is the previous LTS. Java 11 includes several new features and removes some deprecated APIs.

New Features in Java 11

import java.net.http.*;
import java.util.*;
import java.io.*;
import java.nio.file.*;

public class Java11Features {
    public static void main(String[] args) throws Exception {
        
        System.out.println("=== New Features in Java 11 ===
");
        
        // 1. HTTP Client API (standardized)
        System.out.println("1. HTTP Client API:");
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create("https://api.example.com/data"))
            .GET()
            .build();
        System.out.println("  HttpClient is now standard (previously in java 9 as incubator)
");
        
        // 2. Local variable syntax for lambda (var)
        System.out.println("2. Local variable syntax for lambda:");
        List list = Arrays.asList("a", "b", "c");
        list.stream()
            .map((@NotNull var s) -> s.toUpperCase())
            .forEach(System.out::println);
        System.out.println("  var can be used in lambda parameters
");
        
        // 3. New String methods
        System.out.println("3. New String Methods:");
        String str = "  Hello  ";
        System.out.println("  Original:  + str + ");
        System.out.println("  isBlank(): " + str.isBlank());
        System.out.println("  strip():  + str.strip() + ");
        System.out.println("  stripLeading():  + str.stripLeading() + ");
        System.out.println("  stripTrailing():  + str.stripTrailing() + ");
        
        String multiline = "Line1
Line2
Line3";
        System.out.println("  lines():");
        multiline.lines().forEach(line -> System.out.println("    " + line));
        
        System.out.println("  repeat(3): " + "Hi".repeat(3) + "
");
        
        // 4. Files.readString/writeString
        System.out.println("4. Files.readString/writeString:");
        Path path = Files.writeString(Files.createTempFile("test", ".txt"), "Hello Java 11");
        String content = Files.readString(path);
        System.out.println("  File content: " + content + "
");
        
        // 5. Collection to array with better syntax
        System.out.println("5. Collection to array:");
        List names = List.of("Alice", "Bob", "Charlie");
        String[] array = names.toArray(String[]::new);
        System.out.println("  Array: " + Arrays.toString(array) + "
");
        
        // 6. Not() method in Predicate (Java 11)
        System.out.println("6. Predicate.not():");
        List words = Arrays.asList("hello", "", "world", "", "java");
        long nonEmptyCount = words.stream()
            .filter(Predicate.not(String::isEmpty))
            .count();
        System.out.println("  Non-empty strings: " + nonEmptyCount);
    }
}

Removed/Deprecated in Java 11

public class Java11Removals {
    public static void main(String[] args) {
        System.out.println("=== Removed/Deprecated in Java 11 ===
");
        
        // 1. REMOVED: Java EE and CORBA modules
        System.out.println("1. Removed Java EE and CORBA modules:");
        System.out.println("   - java.xml.ws (JAX-WS)");
        System.out.println("   - java.xml.bind (JAXB)");
        System.out.println("   - java.activation (JAF)");
        System.out.println("   - java.corba");
        System.out.println("   - java.transaction");
        System.out.println("   - Use external libraries instead
");
        
        // 2. DEPRECATED: Nashorn JavaScript Engine
        System.out.println("2. Deprecated Nashorn JavaScript Engine:");
        System.out.println("   - Use GraalVM JavaScript instead
");
        
        // 3. REMOVED: Applet API
        System.out.println("3. Removed Applet API:");
        System.out.println("   - Applet class removed
");
        
        // 4. REMOVED: Java Web Start
        System.out.println("4. Removed Java Web Start
");
        
        // 5. REMOVED: com.sun.awt.AWTUtilities
        System.out.println("5. Removed com.sun.awt.AWTUtilities
");
        
        // 6. REMOVED: Thread.destroy() and Thread.stop(Throwable)
        System.out.println("6. Removed Thread.destroy() and Thread.stop(Throwable)
");
        
        // 7. Removed finalize() method (deprecated)
        System.out.println("7. finalize() method deprecated for removal
");
    }
}

Performance and Security Improvements

public class Java11Performance {
    public static void main(String[] args) {
        System.out.println("=== Performance and Security Improvements ===
");
        
        // 1. ChaCha20-Poly1305 encryption (new cipher)
        System.out.println("1. New Cipher: ChaCha20-Poly1305");
        System.out.println("   - Modern encryption algorithm
");
        
        // 2. TLS 1.3 support
        System.out.println("2. TLS 1.3 Support");
        System.out.println("   - Improved security and performance
");
        
        // 3. Improved Garbage Collection
        System.out.println("3. Garbage Collection Improvements:");
        System.out.println("   - ZGC (Z Garbage Collector) - low latency");
        System.out.println("   - Shenandoah GC - ultra-low pause times");
        System.out.println("   - Epsilon GC - no-op GC for testing
");
        
        // 4. Flight Recorder (JFR) - open source
        System.out.println("4. Java Flight Recorder (JFR)");
        System.out.println("   - Now open source (was commercial in Java 8)");
        System.out.println("   - Low-overhead profiling
");
        
        // 5. Unicode 10 support
        System.out.println("5. Unicode 10 Support");
        System.out.println("   - More emojis and characters
");
        
        // 6. Compact strings (improved memory)
        System.out.println("6. Compact Strings");
        System.out.println("   - Strings use byte[] instead of char[] when possible");
        System.out.println("   - Reduces memory usage
");
        
        // 7. Nest-based access control
        System.out.println("7. Nest-Based Access Control");
        System.out.println("   - Improved reflection performance for inner classes
");
        
        // 8. Dynamic class-file constants
        System.out.println("8. Dynamic Class-File Constants");
        System.out.println("   - New constant pool format
");
    }
}

Migration Considerations

import java.util.*;
import java.lang.module.*;

public class MigrationGuide {
    public static void main(String[] args) {
        System.out.println("=== Migration from Java 8 to Java 11 ===
");
        
        // Check Java version
        String version = System.getProperty("java.version");
        String vendor = System.getProperty("java.vendor");
        System.out.println("Current Java: " + version + " (" + vendor + ")");
        
        System.out.println("
=== Migration Steps ===");
        System.out.println("1. Analyze dependencies using jdeps");
        System.out.println("2. Update third-party libraries to Java 11 compatible versions");
        System.out.println("3. Replace removed APIs (Java EE, CORBA, etc.)");
        System.out.println("4. Update build tools (Maven/Gradle)");
        System.out.println("5. Test thoroughly with Java 11");
        System.out.println("6. Consider modularization (module-info.java)
");
        
        System.out.println("=== Module System Changes ===");
        System.out.println("Java 9+ introduced module system (project Jigsaw)");
        System.out.println("- module-info.java defines module dependencies");
        System.out.println("- Strong encapsulation by default");
        System.out.println("- Use --add-exports to open modules");
        
        System.out.println("
=== Reflection Changes ===");
        System.out.println("Deep reflection on JDK internals:");
        System.out.println("- Illegal reflective access issues warnings in Java 9-16");
        System.out.println("- Illegal reflective access forbidden in Java 17+");
        System.out.println("- Use --illegal-access=permit to maintain Java 8 behavior");
        
        System.out.println("
=== Version Naming ===");
        System.out.println("Java 8: 1.8.0_xxx");
        System.out.println("Java 11: 11.0.x");
        System.out.println("Java 17: 17.0.x");
        
        System.out.println("
=== Runtime Changes ===");
        System.out.println("- JRE no longer provided separately");
        System.out.println("- Use jlink to create custom runtime images");
        System.out.println("- java -version gives different output format");
        
        // jdeps example
        System.out.println("
=== Analyze Dependencies ===");
        System.out.println("Command: jdeps --jdk-internals --multi-release 11 MyApp.jar");
        System.out.println("Lists internal API usage that may break in Java 11");
    }
}

Comparison Table

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