Java 11 - Overview

Every 6 months, Oracle releases out new Java versions. The September Java 11 version is already making a lot of buzz in the computer science world even before it was released by declaring that from now on Java is gonna be paid for commercial use.
Following articles will show important features, enhancements and deprecated features about JDK 11.

Important Changes and Information

• The deployment stack required for running applets and web applications has been removed from JDK which was deprecated in JDK 9.
• Entire section of supported browsers has been removed from list of supported configurations due to unavailability of deployment stack.
• Auto-update has been removed from JRE installations in Windows and MacOS.
• JavaFX and Java Mission Control is now available as a separate download.
• Java language translation for French, German, Italian, Korean, Portuguese (Brazilian), Spanish, and Swedish is no longer provided.
• In this version, JRE or Server JRE is no longer offered. Only JDK is offered.
• Updated packaging format for Windows has changed from tar.gz to .zip
• Updated package format for macOS has changed from .app to .dmg

New Features and Enhancements

1. New String methods:
   • isBlank(): This is a boolean method. It just returns true when a string is empty and vice-versa.

     class EYT {
         public static void main(String args[])
         {
             String str1 = "";
             System.out.println(str1.isBlank());
       
             String str2 = "eTheRealYT";
             System.out.println(str2.isBlank());
         }
     } 

     Output:
     
     

     True
     False

   • lines(): This method is to return a collection of strings which are divided by line terminators.

    class EYT {
       public static void main(String args[])
       {
        String str = "Hello\nWorld";
        System.out.println(str
                .lines()
                .collect(
                 Collectors.toList()));
       }
        }

   Output:
   

   Hello 
   World

   • repeat(n): Result is the concatenated string of original string repeated the number of times in the argument.

     class EYT {
         public static void main(String args[])
         {
             String str = "HelloWorld";
             System.out.println(str.repeat(4));
         }
     }

     Output:
     

     HelloWorldHelloWorldHelloWorldHelloWorld
     

   • stripLeading(): It is used to remove the white-space which is in-front of the string

     class EYT {
         public static void main(String args[])
         {
             String str = " Hello World";
             System.out.println(str.stripLeading());
         }
     }

     Output:
     

     Hello World

   • stripTrailing(): It is used to remove the white-space which is in back of the string

     class EYT {
         public static void main(String args[])
         {
             String str = "Hello World ";
             System.out.println(str.stripTrailing());
         }
     }

     Output:
     

     Hello World

   • strip(): It is used to remove the white-spaces which are in-front and back of the string

     class EYT {
         public static void main(String args[])
         {
             String str = " Hello World ";
             System.out.println(str.strip());
         }
     }

     Output:
     

     Hello World

2. New File Methods
   • writeString():- This is to write some content in a file.

     jshell>Files.writeString(Path.of(example.txt), "GeeksForGeeks!");

   • readString():- This is used to read the contents of a file.

     jshell>Files.readString(Path.of(example.txt));
     
     Output: "Hello World!"
     

   • isSameFile():-This method is used to know whether two paths locate the same file or not.

     jshell>Files.isSameFile(Path.of("example1.txt"), Path.of("example1.txt"));
     Output: true
     
     jshell>Files.isSameFile(Path.of("example2.txt"), Path.of("example1.txt"));
     Output: false
     

3. Pattern recognizing methods:
   • asMatchPredicate():- This method is similar to Java 8 method asPredicate(). Introduced in JDK 11, this method will create a predicate if pattern matches with input string.

     jshell>var str = Pattern.compile("aba").asMatchPredicate();
     
     jshell>str.test(aabb);
     Output: false
     
     jshell>str.test(aba);
     Output: true
     

4. Epsilon Garbage Collector: This handles memory allocation but does not have actual memory reclamation mechanism. Once the available Java heap is exhausted, JVM will shut down.
   Its goals are:-
   
   • Performance testing
   • Memory pressure testing
   • last drop latency improvements
5. Removed the Java EE and CORBA modules: These modules were deprecated in Java 9 with declaration to remove those in further JDK versions.
6. Removal of thread functions: stop(Throwable obj) and destroy() objects have been removed from the JDK 11 because they only throw UnSupportedOperation and NoSuchMethodError respectively. Other than that, they were of no use.
7. TimeUnit Conversion: This method is used to convert the given time to a unit like DAY, MONTH, YEAR and for time too.

   jshell>TimeUnit c = TimeUnit.DAYS;
   Output: DAYS
   
   jshell>c.convert(Duration.ofHours(24));
   Output: 1
   
   jshell>c.convert(Duration.ofHours(50));
   Output: 2
   

8. Optional.isEmpty() This method returns true if the value of any object is null and else returns false.

   jshell>Optional str = Optional.empty();
   jshell>str.isEmpty();
   Output: true
   
   jshell>Optional str = Optional.of("TonyStark");
   jshell>str.isEmpty();
   Output: false
   

9. Local-Variable Syntax for Lambda Parameters: JDK 11 allows ‘var’ to be used in lambda expressions. This was introduced to be consistent with local ‘var’ syntax of Java 10.

   //Variable used in lambda expression
     
           public class VarInLambdaExample {
             public static void main(String[] args) {
              IntStream.of(1, 2, 3, 5, 6, 7)
                 .filter((var i) -> i % 2 == 0)
                 .forEach(System.out::println);
             }
           }

   Output:
   

   2
   6

   //Variable without using lambda expression
     
             public class WithoutVarInLambdaExample {
               public static void main(String[] args) {
                IntStream.of(1, 2, 3, 5, 6, 7)
                   .filter(i -> i % 2 == 0)
                   .forEach(System.out::println);
               }
           }

   Output:
   

   2
   6
   

Removed Features and Options

1. Removal of com.sun.awt.AWTUtilities Class
2. Removal of Lucida Fonts from Oracle JDK
3. Removal of appletviewer Launcher
4. Oracle JDK’s javax.imageio JPEG Plugin No Longer Supports Images with alpha
5. Removal of sun.misc.Unsafe.defineClass
6. Removal of Thread.destroy() and Thread.stop(Throwable) Methods
7. Removal of sun.nio.ch.disableSystemWideOverlappingFileLockCheck Property
8. Removal of sun.locale.formatasdefault Property
9. Removal of JVM-MANAGEMENT-MIB.mib
10. Removal of SNMP Agent
11. Removal of Java Deployment Technologies
12. Removal of JMC from the Oracle JDK
13. Removal of JavaFX from the Oracle JDK
14. JEP 320 Remove the Java EE and CORBA Modules

Deprecated Features and Options

1. ThreadPoolExecutor Should Not Specify a Dependency on Finalization
2. JEP 335 Deprecate the Nashorn JavaScript Engine
3. Deprecate -XX+AggressiveOpts
4. Obsolete Support for Commercial Features
5. Deprecate Stream-Based GSSContext Methods
6. JEP 336 Deprecate the Pack200 Tools and API