How to Convert Stream to ArrayList in Java 8 - Collectors.toCollection() Example, Tutorial

You can use Collectors.toList(), toSet() and toMap() to get all elements of Stream into any Collection e.g. List, Set or Map, but if you want to get a particular collection e.g. ArrayList, then you need to use Collectors.toCollection(ArrayList::new) method. This method first creates an ArrayList using method reference and then adds all elements of Stream into the ArrayList. It's very useful if you have a long list of String and you want to create a smaller list containing only String starting with the letter "b" e.g. "Bluehost". All you need to do is first get the stream from List by calling stream() method, then call the filter() method to create a new Stream of filtered values and finally call the Collectors.toCollection(ArrayList::new) to collect those elements into an ArrayList.

3 Examples to Loop Through a List in Java 8

3 ways to Loop through a List in Java
There are multiple ways to traverse or loop through a List in Java e.g. by using an Iterator, by using an enhanced for loop of Java 5, and not the forEach() method of Java 8. Given a List is an index-based collection if you know the index you can retrieve an object from List and because of this, you can also use traditional for loop which keeps count for iterating List. Now the question is whether should you use the Iterator or enhanced for loop, or the forEach() method of Java 8 for looping over List in Java. 

Difference between synchronized block and method in Java Thread

Synchronized block and synchronized methods are two ways to use synchronized keyword in Java and implement mutual exclusion on critical section of code. Since Java is mainly used to write multi-threading programs,  which present various kinds of thread related issues like thread-safety, deadlock and race conditions, which plagues into code mainly because of poor understanding of synchronization mechanism provided by Java programming language. Java provides inbuilt synchronized and volatile keyword to achieve synchronization in Java. Main difference between synchronized method and synchronized block is selection of lock on which critical section is locked.

Difference between Callable and Runnable in Java - Thread Interview question

The difference between the Callable and Runnable interface in Java is one of the interesting questions from my list of Top 15 Java multi-threading questions, and it’s also very popular in various Java Interviews. The Callable interface is newer than the Runnable interface and added on Java 5 release along with other major changes e.g. Generics, Enum, Static imports, and variable argument method. Though both Callable and Runnable interface are designed to represent a task, which can be executed by any thread, there is some significant difference between them. In my opinion, the major difference between the Callable and Runnable interface is that Callable can return the result of an operation performed inside the call() method, which was one of the limitations of the Runnable interface.

10 points about Thread in Java

Thread in Java is one of those topics which always confuse beginners but given its importance and strength it provides to the Java language, it's very important for every Java developer to learn and understand the fundamental concept of multi-threading and basic points about Thread in Java. I had started thread programming in Java by animating a couple of words in Applets, that was an amazing experience to code animation, but after spending almost 10 years on developing core Java applications and I am still discovering things about threading and concurrency. My first program which involves Thread had three words dropping from each corner of the screen and I was excited to see that animation driven by Java thread.