What Java Has Removed from C++

1. Pointers. Pointers don't exist in Java for two reasons:
• Pointers are inherently insecure. For example, using a C++-style pointer, it is possible to gain access to memory addresses outside a program's code and data. A malicious program could make use of this fact to damage the system, perform unauthorized accesses (such as obtaining passwords), or otherwise violate security restrictions.
• Even if pointers could be restricted to the confines of the Java run-time system (which is theoretically possible, since Java programs are interpreted), the designers of Java believed that they were inherently troublesome. 
2. Java does not include structures or unions. These were felt to be redundant since the class encompasses them.
3. Java does not support operator overloading. Operator overloading is sometimes a source of ambiguity in a C++ program, and the Java design team felt that it causes more trouble than benefit.
4. Java does not include a preprocessor nor does it support the preprocessor directives. The preprocessor plays a less important role in C++ than it does in C. The designers of Java felt that it was time to eliminate it entirely.
5. Java does not perform any automatic type conversions that result in a loss of precision. For example, a conversion from long integer to integer must be explicitly cast.
6. All the code in a Java program is encapsulated within one or more classes. Therefore, Java does not have what you normally think of as global variables or global functions.
7. Java does not allow default arguments. In C++, you may specify a value that a parameter will have when there is no argument corresponding to that parameter when the function is invoked. This is not allowed in Java.
8. Java does not support the inheritance of multiple super classes by a subclass.
9. Although Java supports constructors, it does not have destructors. It does, however, add the finalize ( ) function.
10. Java does not support typedef.
11. It is not possible to declare unsigned integers in Java.
12. Java does not allow the goto.
13. Java does not have the delete operator.
14. The << and >> in Java are not overloaded for I/O operations.
15. In Java, objects are passed by reference only. In C++, objects may be passed by value or by reference.

Loads of Love,
Ravi