Java 8 Features and Multithreading

Java 8 Features

Lambda Expressions

• A concise way to represent a single-method interface
• Allows for functional programming
• Syntax: (parameters) -> {code}

Functional Interfaces

• An interface with a single abstract method (SAM)
• Can be used with lambda expressions
• Examples: Runnable, Callable

Method References

• A shorthand for lambda expressions
• Syntax: Classname::methodName
• Can be used to refer to existing methods or constructors

Default Methods

• Allows adding new methods to interfaces without breaking existing implementations
• Can be used to provide default implementations for interface methods
• Syntax: default return-type methodName(parameters) {code}

Optional Class

• A container for a value that may or may not be present
• Can be used to avoid null pointer exceptions
• Methods: isPresent(), get(), orElse()

Multithreading

Thread Creation

• Can be created using Thread class or Runnable interface
• Thread class provides a start() method to start the thread
• Runnable interface provides a run() method to be executed by the thread

Thread Synchronization

• Used to coordinate access to shared resources
• Methods: synchronized block, wait(), notify(), notifyAll()

Thread Safety

• Ensuring that multiple threads can access shared resources without causing errors
• Techniques: atomic operations, locks, immutable objects

Deadlock

• A situation where two or more threads are blocked indefinitely
• Caused by circular dependencies between threads
• Can be avoided by using deadlock-avoidance algorithms or careful design

Thread States

• Newborn: thread is created but not started
• Runnable: thread is running or ready to run
• Running: thread is currently executing
• Waiting: thread is waiting for some event to occur
• Sleeping: thread is sleeping for a specified amount of time
• Blocked: thread is blocked due to I/O or synchronization
• Dead: thread has finished execution

Test your knowledge of Java 8 features such as lambda expressions, functional interfaces, and method references, as well as multithreading concepts like thread creation, synchronization, and deadlock avoidance.