Java 8 Interview Questions and Answers
JAVA is an open-source object-oriented programming language that is secure and robust. JAVA is the language that can run on all the platforms which support JAVA without recompilation. More than 3 billion devices run on Java. JAVA is used for developing Mobile applications, Desktop applications, Web servers, and application servers etc.JAVA was developed by James Gosling at Sun Microsystems now ORACLE in the year 1995.
The Java 8 interview questions we are mentioning below will help you to gain enough of the knowledge about Fortran.
- Introduction of Lambda Expression- first step to functional programming
- New stream API to supports pipeline processing.
- Optional − Emphasis on handling null values properly.
- Nashorn Engine- Provides better performance than Rhino javascript engine.
| JAVA 8 | |
|---|---|
| What is JAVA 8? | JAVA 8 is one of the versions of JAVA programming which was released on March 18, 2014. |
| Latest Version | Java SE 1317th September 2019 |
| Developed By | Sun Microsystems |
| Designed By | James Gosling |
Most Frequently Asked Java 8 Interview Questions
| S.no | Intermediate | Terminal |
|---|---|---|
| 1. | The intermediate operation produces stream pipelining | Terminal operation terminate the pipeline |
| 2. | Intermediate operations can be chained multiple times on a stream | Terminal operations cannot be chained various times. |
| 3. | Intermediate operations cannot be evaluated independently; it needs a terminal operation for evaluation. | Terminal Operations can be evaluated independently. |
Functional interfaces are those interfaces that have a single functionality.
- CompareTo--- This interface is only for comparison purposes.
- Function
---this interface accepts only one argument and gives the result.
This interface means that an object is tested to be either true or false.
New features introduced in Java 8 are:-
- Introduction of Lambda Expression- first step to functional programming
- New stream API to support pipeline processing.
- Optional − Emphasis on handling null values properly.
- Nashorn Engine- Provides better performance than Rhino javascript engine.
Lamba expression is considered as the most significant feature of Java8. A Lambda expression provides functional programming, and that has simplified the code to a great extent. A lambda expression is fundamentally a function which can be created without belonging to any class.
Method references support in pointing to the methods by their names. A method reference is denoted by using "::" symbol. A method reference is used to indicate the following methods
- Static methods
- Instance methods
- Constructors using new operator (TreeSet::new)
This is a fundamental question in java 8 interview questions.
The valueOf() method converts data into human-readable form.So String valueOf() will return the string representation of the value. The valueOf() method is a static method.
- String valueOf(inum)--this syntax will return the string representation of the integer inum.
- String.valueOf(data, 0, 5)-- This syntax will return the string representation of the character Array 0 to 5
- String.valueOf(fNum) --this syntax will return the string representation of the float fNum
In java there a NullPointerException which can crash the code. It is complicated to remove the null checks from the code. Java 8 introduced Optional class in java. util package. Use of Optional class results in clean code without null checks. By using the Optional class, the programmer can specify the other value or other code to return. This makes the code more readable.
The default method implementation was introduced by Java 8 so that the old interfaces can use the lambda expression without implementing the methods in the implementation class.
Syntax:-
public interface interview {
default void print() {
System.out.println("Welcome Bestinterviewquestion.com");
}
}
The syntax for the Lambda expression is:-
parameter -> expression body
Characteristics of the Lambda Expression:-
- No need to declare the parameter type as the compiler will get the standard by the value of the parameter.
- For the multiple parameters parenthesis has to be declared, but for the simple parameter, parenthesis need not be declared.
- If a contains only a single parameter, then there is no need of curly braces.
Along with Java 8, a new improved engine Nashorn was introduced. Nashorn gives very high performance because it straightaway compiles the program code in the memory and then passes the bytecode to JVM. It uses the invoke dynamics feature of Java 7 to improve the performance.
What is JAVA 8?
JAVA 8 is one of the versions of JAVA programming language which was released on March 18, 2014. Java8 provides supports for functional programming, new JavaScript engine Nashorn, new APIs for the date and time manipulation, new streaming API, etc. Now the coding has become simple.