JDK11 Features and Changes.
Important Changes:
- The deployment stack, required for Applets and Web Start Applications, was deprecated in JDK 9 and has been removed in JDK 11.
- In Windows and macOS, installing the JDK in previous releases optionally installed a JRE. In JDK 11, this is no longer an option.
- In this release, the JRE or Server JRE is no longer offered. Only the JDK is offered. Users can use jlink to create smaller custom runtimes.
- JavaFX is no longer included in the JDK. It is now available as a separate download from openjfx.io.
- Java Mission Control, which was shipped in JDK 7, 8, 9, and 10, is no longer included with the Oracle JDK. It is now a separate download.
- Updated packaging format for Windows has changed from tar.gz to .zip.
- Updated package format for macOS has changed from .app to .dmg.
Features:
1)Local-Variable Syntax for Lambda Parameters:
IntFunction<Integer> d1 = (int x) -> x * 2; // Valid
IntFunction<Integer> d2 = (var x) -> x * 3; // Generets Error
The second line won’t compile in Java 10, but will compile in Java 11.
But, why do we need that at all? If we can write it like this:
IntFunction<Integer> d1 = x -> x * 3;
2) String::lines
Another new feature in Java 11 is the ‘String::lines’ which helps in streaming lines.This is ideal for situations where you have a multiline string.
var str = "This\r\n is \r\nSrinivas";
str.lines()
// we now have a `Stream<String>`
.map(line -> "// " + line)
.forEach(System.out::println);
// OUTPUT:
// This
// is
// Srinivas
3) toArray(IntFunction) Default Method:
After the Java 11 release date, another new feature in Java 11 also comes to the front. The new feature is the .toArray(IntFunction) default method, which is now a part of the ‘java.util.Collection’ interface. The method helps in transferring elements in the collection to a newly created array having specific runtime type. You can assume it as an overload of the toArray (T[ ]) method used for taking array instance as an argument.
4) Epsilon Garbage Collector:
The addition of JEP 318 Epsilon to the top Java 11 features is also another notable highlight. The No-Op garbage collector is ideal for handling only memory allocation without implementing any memory reclamation apparatus. Epsilon GC is also helpful for cost-benefit comparison of other garbage collectors and performance testing.
5) Improved KeyStore Mechanisms:
Security precedents for Java 12 features can take inspiration from Java 11. The new and improved KeyStore mechanisms in Java 11 can surely provide a valid proof for that. You can find a new security property with the name ‘jceks.key.serialFilter’ in Java 11.
JCEKS KeyStore users this security filter at the time of deserialization of encrypted key object housed in a SecretKeyEntry. Without any configuration, the filter result renders an UNDECIDED value and obtains default configuration by ‘jdk.serialFilter.’
6) Z Garbage Collector:
One of the crucial new entries in top Java 11 features is the ZGC or Z garbage collector. It is a scalable low-latency garbage collected ideal for addressing specific objectives. The Z garbage collector ensures that pause times do not go beyond 10ms. It also ensures that pause times do not increase with the size of the heap or live-set. Finally, ZGC also manages heaps of varying sizes from 100 megabytes to multi terabytes.
7) Dynamic Allocation of Compiler Threads:
Dynamic control of compiler threads is possible now in Java 11 with a new command line flag. The command-line flag is ‘-XX: +UseDynamicNumberOfCompilerThreads.’ The VM starts numerous compiler threads on systems with multiple CPUs in the tiered compilation mode. There is no concern for the number of compilation requests or available memory with this command line flag.
8) New File Methods:
New file methods among Java 11 features are also prominent attractions in the new Java release. The new file methods include ‘writeString()’, ‘readString()’ and ‘isSameFile()’. ‘writeString()’ is ideal for writing some content in a file while ‘readString()’ is ideal for reading contents in a file.
9) isBlank():
This is a boolean method. It just returns true when a string is empty and vice-versa.
class Blog {
public static void main(String args[])
{ String str1 = "";
System.out.println(str1.isBlank());
String str2 = "SriniBlog";
System.out.println(str2.isBlank());
}}
10) lines(): This method is to return a collection of strings which are divided by line terminators.
class Blog {
public static void main(String args[])
{
String str = "Blog\nFor\nSrini";
System.out.println(str
.lines()
.collect(
Collectors.toList()));
}}
11) 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.
12) 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 LambdaExample {
public static void main(String[] args) {
IntStream.of(1, 2, 3, 5, 6, 7)
.filter((var i) -> i % 2 == 0)
.forEach(System.out::println);
}}
13) 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("aa").asMatchPredicate();
jshell>str.test(aabb);
Output: false
jshell>str.test(aa);
Output: true
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
