Java BuzzWords - 4

Robust

Java is intended for writing programs that must be reliable in a variety of ways. Java puts a lot of emphasis on early checking for possible problems, later dynamic (runtime) checking, and eliminating situations that are error prone.

One of the advantages of a strongly typed language (like C++) is that it allows extensive compile-time checking so bugs can be found early. Unfortunately, C++ inherits a number of loopholes in compile-time checking from C, which is relatively lax (particularly method/procedure declarations). In Java, we require declarations and do not support C-style implicit declarations.The linker understands the type system and repeats many of the type checks done by the compiler to guard against version mismatch problems.

The single biggest difference between Java and C/C++ is that Java has a pointer model that eliminates the possibility of overwriting memory and corrupting data. Instead of pointer arithmetic, Java has true arrays. This allows subscript checking to be performed. In addition, it is not possible to turn an arbitrary integer into a pointer by casting.While Java doesn't make the QA problem go away, it does make it significantly easier.

Very dynamic languages like Lisp, TCL and Smalltalk are often used for prototyping. One of the reasons for their success at this is that they are very robust: you don't have to worry about freeing or corrupting memory. Java programmers can be relatively fearless about dealing with memory because they don't have to worry about it getting corrupted. Because there are no pointers in Java, programs can't accidentally overwrite the end of a memory buffer. Java programs also cannot gain unauthorized access to memory, which could happen in C or C++.

One reason that dynamic languages are good for prototyping is that they don't require you to pin down decisions too early. Java uses another approach to solve this dilemma; Java forces you to make choices explicitly because it has static typing, which the compiler enforces. Along with these choices comes a lot of assistance: you can write method invocations and if you get something wrong, you are informed about it at compile time. You don't have to worry about method invocation error.