Basic Tructure:

jse.executeScript("line 1" +
                "line 2" +
                "line 3" +
                "line 4" +
                "line 5" +
                "line 6" +
                "line 7");

Java Code:

JavascriptExecutor jse = (JavascriptExecutor) driver;
        jse.executeScript(
                "var s=window.document.createElement('script');" +
                "s.type = 'text/javascript';" + "s.text = function foo() {console.log('foo')};" +
                "window.document.body.appendChild(s);"+
                "foo();"+ 
                "alert('Hello, Nikhil');"
        );

code work perfectly in selenium java