What's the difference between JavaScript and Java?

Answer 1

A Re-Introduction to Javascript by the Mozilla team (they make Firefox) should explain it.

Answer 2

Don't be confused with name..
Java was created at Sun Microsystems (now Oracle).
But, JavaScript was created at Netscape (now Mozilla) in the early days of the Web, and technically, “Java-Script” is a trademark licensed from Sun Microsystems used to describe Netscape’s implementation of the language. Netscape submitted the language for standardization to ECMA (European Computer Manufacturer’s Association) and because of trademark issues, the standardized version of the language was stuck with the awkward name “ECMAScript.” For the same trademark reasons, Microsoft’s version of the language is formally known as “JScript.” In practice, just about everyone calls the language JavaScript. The real name is “ECMAScript”.

Both are fully different languages!!!

Answer 3

Here are some differences between the two languages:

• Java is a statically typed language; JavaScript is dynamic.
• Java is class-based; JavaScript is prototype-based.
• Java constructors are special functions that can only be called at object creation; JavaScript "constructors" are just standard functions.
• Java requires all non-block statements to end with a semicolon; JavaScript inserts semicolons at the ends of certain lines.
• Java uses block-based scoping; JavaScript uses function-based scoping.
• Java has an implicit this scope for non-static methods, and implicit class scope; JavaScript has implicit global scope.

Here are some features that I think are particular strengths of JavaScript:

• JavaScript supports closures; Java can simulate sort-of "closures" using anonymous classes. (Real closures may be supported in a future version of Java.)
• All JavaScript functions are variadic; Java functions are only variadic if explicitly marked.
• JavaScript prototypes can be redefined at runtime, and has immediate effect for all referring objects. Java classes cannot be redefined in a way that affects any existing object instances.
• JavaScript allows methods in an object to be redefined independently of its prototype (think eigenclasses in Ruby, but on steroids); methods in a Java object are tied to its class, and cannot be redefined at runtime.

Answer 4

Practically every PC in the world sells with at least one JavaScript interpreter installed on it.

Most (but not "practically all") PCs have a Java VM installed.

Answer 5

Like everybody's saying, they're pretty much entirely different.

However, if you need a scripting language for your Java application, Javascript is actually a really good choice. There are ways to get Javascript running in the JVM and you can access and manipulate Java classes pretty seamlessly once you do.

Answer 6

One is essentially a toy, designed for writing small pieces of code, and traditionally used and abused by inexperienced programmers.

The other is a scripting language for web browsers.