Java 14 was released on March 17, 2020. Let’s see its new features.

Syntax features

JEP 361: Switch Expressions

New switch syntax was proposed in Java 12 as JEP 325: Switch Expressions (Preview) later it was slightly changed in JEP 354: Switch Expressions (Second Preview)

Finally, it became a standard feature, example of syntax:

int cost = switch (day) {
  case MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY  -> {
    yield 1;
  }
  case SATURDAY, SUNDAY -> {
    yield 2;
  }
};

JEP 368: Text Blocks (Second Preview)

This feature was proposed in Java 13, but was not included into standard. It got two new escape sequences:

• \ - to indicate a new line,
• \s - to indicate a single space.

String can be written in a way:

String JSON2 = """
{ \
  "version": 13, \
  "language": "java" \
} \
""";

JEP 305: Pattern Matching for instanceof (Preview)

A new instanceof has been introduced to Java 14. The syntax eliminates boilerplate code:

if (obj instanceof String s) { 
  // you can use variable s here
}

JEP 359: Records (Preview)

Records were introduced as preview feature. It is immutable class, example:

public record User(int id, String name) { };

Record generates for us:

• private final fields,
• getters,
• constructor with all fields,
• equals method,
• hashCode method,
• toString method.

By using record you can still:

• redefine generated constructor, e.g. by adding validation,
• add a different constructor,
• add methods,
• implement interfaces.

By using record you can't:

• extend a class nor can it be extended by another class,
• be abstract,

Compact constructor is a syntax that allows adding of some common logic, e.g. validation when canonical constructor is called.

public record User(int id, String name) {
  public User {
    if(id< 100) {
      throw new java.lang.IllegalArgumentException(String.format("Invalid id: %d",id));
    }
  }
}

Explicit declaration of field accessor method:

public String name() {
  System.out.println(name);
  return name;
}

JEP 358: Helpful NullPointerExceptions

In Java 14 were introduced a more descriptive NullPointerExceptions, example:

User user = null;
int id = user.getId();

Exception:

java.lang.NullPointerException: Cannot invoke "com.java.Java12$User.getId()"
    because "user" is null

JEP 370: Foreign-Memory Access API (Incubator)

Introduce an API to allow Java programs to safely and efficiently access foreign memory outside of the Java heap.

JEP 343: Packaging Tool (Incubator)

From Java 11 JavaFX did not belong to JDK. Also tool javapackager was no longer available. In Java 14 a new tool was introduced jpackage. It packages whole application with JDK into executable file.

JEP 365: ZGC on Windows (Experimental), JEP 364: ZGC on macOS (Experimental)

ZGC was introduced in Java 13. Java 14 has ported its support to Windows and macOS as well.

JEP 345: NUMA-Aware Memory Allocation for G1

Improve G1 performance on large machines by implementing NUMA-aware memory allocation.

JEP 349: JFR Event Streaming

JDK Flight Recorder was introduced in Java 11, now data are exposed for continuous monitoring.

Cleanings

Here I will only mention the most important cleanings made in the JDK.

• Concurrent Mark Sweep (CMS) Garbage Collector (JEP 363) – has been deprecated by Java 9, now has been removed. The recommendation is to use G1. Also there are other alternatives, e.g. ZGC, Shenandoah.
• Pack200 Tools and API (JEP 367) – was deprecated by Java 11, now has been removed.

Summary

Java 14 brought many preview features as standard. For me, it will always stay in memory as the version of Java which proposed experimental version of records.