With Java 8, Nashorn, a way improved javascript engine is introduced, to exchange the prevailing Rhino. Nashorn provides 2 to 10 times better performance because it directly compiles the code in memory and passes the bytecode to JVM. Nashorn uses the invoke dynamics feature, introduced in Java 7 to enhance performance.
Java 8 launched a new command-line tool for Nashorn Engine. jjs, to accomplish javascript codes at solace.
Create and save the file with the name called sample.js in c:\> JAVA folder.
Sample.js print('Hello World!'); Open Console and type the given Command. C:\JAVA>jjs sample.js It Will give the following output: Hello World!
Open Console and use the following command:
C:\JAVA>jjs jjs> print("Hello, World!") Hello, World! jjs> quit() >>
Again Open Console and type the given command
C:\JAVA> jjs -- a b c jjs> print('letters: ' +arguments.join(", ")) letters: a, b, c jjs>
You can use Script Engine Manager, via this javascript code can be called and explain in Java
Example
Create the below-given java program in any editor of your choice in, say, C:\> JAVA.
Java8Tester.java import javax.script.ScriptEngineManager; import javax.script.ScriptEngine; import javax.script.ScriptException; public class Java8Tester { public static void main(String args[]) { ScriptEngineManager scriptEngineManager = new ScriptEngineManager(); ScriptEngine nashorn = scriptEngineManager.getEngineByName("nashorn"); String name = "Mahesh"; Integer result = null; try { nashorn.eval("print('" + name + "')"); result = (Integer) nashorn.eval("10 + 2"); } catch(ScriptException e) { System.out.println("Error executing script: "+ e.getMessage()); } System.out.println(result.toString()); } }
Assemble the class by using javac compiler as follows-
C:\JAVA>javac Java8Tester.java
C:\JAVA>java Java8Tester
The outcome will be: Mahesh 12
Let’s learn how to import and use java classes in Javascript with the help of given example
Now, Create and save sample.js in c:\> JAVA folder.
sample.js
var BigDecimal = Java.type('java.math.BigDecimal'); function calculate(amount, percentage) { var result = new BigDecimal(amount).multiply(new BigDecimal(percentage)).divide( new BigDecimal("100"), 2, BigDecimal.ROUND_HALF_EVEN) return result.toPlainString(); } var result = calculate(568000000000000000023,13.9); print(result);
Open the console and use the following Command:
C:\JAVA>jjs sample.js
Your Product should be this:
78952000000000000003.20