A DESCRIPTION OF THE PROBLEM :
According to ECMA-262 6th edition, nashorn should return 'false' if the argument of 'String.prototype.endsWith' is 'null' , but nashorn throws NullPointerException.
#Testcase:
var foo = function (s, suffix) {
var p=s.endsWith(suffix);
print(p);
};
var Parameter0 = "hello nashorn";
var Parameter1 = null;
foo(Parameter0, Parameter1);

#Command：
./jdk-12.0.1/bin/jjs --language=es6 testcase.js

#Output:
Warning: The jjs tool is planned to be removed from a future JDK release
Exception in thread "main" java.lang.NullPointerException
        at java.base/java.lang.String.endsWith(String.java:1494)
        at jdk.scripting.nashorn.scripts/jdk.nashorn.internal.scripts.Script$Recompilation$1$28060/0x0000000801268440.:program(../test/28060.js:1)
        at jdk.scripting.nashorn/jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:655)
        at jdk.scripting.nashorn/jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:513)
        at jdk.scripting.nashorn/jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:527)
        at jdk.scripting.nashorn/jdk.nashorn.tools.Shell.apply(Shell.java:522)
        at jdk.scripting.nashorn/jdk.nashorn.tools.Shell.runScripts(Shell.java:451)
        at jdk.scripting.nashorn/jdk.nashorn.tools.Shell.run(Shell.java:189)
        at jdk.scripting.nashorn.shell/jdk.nashorn.tools.jjs.Main.main(Main.java:100)
        at jdk.scripting.nashorn.shell/jdk.nashorn.tools.jjs.Main.main(Main.java:76)

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
false