Introduction to Java 8
Oracle rolled out a fresh release of Java on March 18, 2014. This is termed Java 8 and touted as a landmark release with many new as well as useful features. Read on to get acquainted with the features of Java 8. It includes new functionality, upgrades and bug fixes to increase efficiency in designing and operating Java programs.
Top Features of Java 8
Below are the top features of Java 8 that make Java 8 more understanding and more useful:
1. New Date/Time API
The old Date-Time API of Java had major drawbacks. In place of it, there is a fresh Date-Time API in Java 8. We take a look at the drawbacks below:
- Tough to Handle Timezone: Programmers needed many lines of code to tackle timezone issues.
- Low-Quality Design: The earlier API had relatively few direct functions for date operations. Java 8 API offers many functions for date operations.
- Absence of Thread Safe Property: java.util.date lacked thread-safe property. Hence programmers had to face concurrency issues while employing data. Java 8 Date-Time API is immutable and without setter methods.
In Java 8 there is a fresh Date-Time API contained in the package java.time. Below are the 2 significant classes contained in the java. time package.
- Zoned: Specialized API to handle different timezones.
- Local: Simplified API without the complexity of handling timezones.
2. Nashorn JavaScript
The earlier version of Java contained the Rhino JavaScript engine. In Java 8, Rhino is replaced by a superior JavaScript engine namely Nashorn. The latter offers two to ten times superior performance when benchmarked against its predecessor. This is possible as it directly compiles the lines of code in memory followed by passing the bytecode to the Java Virtual Machine. Nashorn employs the invoke dynamics feature of Java 7 in order to enhance performance.
3. Optional Class
Optional simply put is a container object which is employed to store not-null objects. One major use of the Optional object is to represent null having absent value. This important class has different utility methods to help code handle values as ‘not available’ or ‘available’ rather than to check null values. The class was added in Java 8 and is analogous to what the Optional class is in Guava.
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4. Base64
The new version of Java contains an inbuilt encoder as well as a decoder for the purpose of Base64 encoding. Programmers can employ 3 kinds of Base64 encoding.
- MIME: Mapping is done of Output to the MIME format. The representation of the output is done in lines not exceeding 76 characters each. The line separator is a carriage return succeeded by a linefeed. There is no line separator at the termination of the encoded output.
- URL: Mapping of Output is done to a group of characters present in A-Za-z0-9+_. The output is filename as well as the URL safe.
- Simple: Mapping of Output is done to a group of characters present in A-Za-z0-9+_. No addition of any line feed in the output is done by the encoder. The decoder does accept any character differing from A-Za-z0-9+_.
5. Streams
The stream is a fresh abstract layer present in this new version of Java. By employing stream, data can be processed in a declarative manner analogous to that of SQL statements.
Understanding Stream
Stream simply put is a representation of a sequence of objects emanating from a source that has support for aggregate operations. Below are certain properties of a stream.
- Iterations are Automatic: Explicit iterations are mandatory in Collections. Whereas in Stream iterations are done internally over the supplied source elements.
- Pipelining: The majority of the stream operation’s output is of the stream type. Thus, the output can be pipelined. The particular operations are termed intermediate operations. They accept input, do the necessary processing and give the output to the target.
Some Aggregate Operations supported by Stream:
- Match
- Find
- Reduce
- Limit
- Map
- Filter
6. Functional Interfaces
They display individual functionality. The new version of Java has numerous functional interfaces which can be employed in large measure in lambda expressions.
7. Default Methods
In Java 8, there is a fresh paradigm of interfaces having default method implementation. The feature is included for the purpose of backward compatibility. It is now possible to use old interfaces to harness the lambda expression capability of the new version of Java.
For instance: ‘Collection’ and ‘List’ interfaces lack ‘forEach’ method declaration. If such a method is added the collection framework implementations would be broken. Now, the default method is introduced such that List/Collection contains default implementations of the forEach method. Now the respective methods do not have to be implemented by the class which is implementing these particular interfaces.
8. Method References
This major feature of Java 8 use is to point to relevant methods using their respective names. A “::” symbol describes method references. The latter can be employed to point to the below-mentioned kinds of methods-
- Constructors Employing the New Operator
- Instance Methods
- Static Methods
9. Lambda Expressions
These are claimed to be the most important as well as the most significant feature of the new version of Java. The former makes functional programming easy and convenient. Moreover, Lambda expressions simplify programming to a great extent.
Below is a typical lambda expression.
parameter -> body of expression
We take a look at the major parts of a lambda expression.
- Return Keyword: The value is returned by the compiler in case the body contains a single expression. Curly braces signify that the expression returns some value.
- The parenthesis around the parameter: If there is only a single parameter parenthesis can be omitted.
- Type Declaration: Parameter type declaration is not needed. From the parameter’s value, the compiler determines the necessary action.
Miscellaneous Features of Java 8: JDBC-ODBC Bridge has been taken off. So. has been the PermGen memory space. The ‘jjs’ command invokes the Nashorn engine while the ‘jdeps’ command analyzes the class files.
Conclusion
Now that you have a theoretical knowledge of Java 8’s new features it is necessary to put them in action. In other words, you have to do the coding that exploits the many useful and valuable features of the new version of Java. Only then will you be truly proficient in Java 8.
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