New Features Added by Java

Java Features 

There are a number of features in Java that have no equivalent in C++. Perhaps the three most important are multithreading, packages, and interfaces, but there are several others that enrich the Java programming environment as well.

• Multithreading allows two or more pieces of the same program to 
  execute concurrently. Further, this approach to concurrence is supported at the 
  language level. There is no parallel for this in C++. If you need to multithread a C++ 
  program, you will need to do so manually, using operating system functions. While 
  both methods allow for concurrent execution of two or more threads, Java's approach 
  is cleaner and easier to use.
• There is no feature in C++ that directly corresponds to a Java package. The closest 
  similarity is a set of library functions that use a common header file. However, 
  constructing and using a library in C++ is completely different from constructing and 
  using a package in Java.
• The Java interface is somewhat similar to a C++ abstract class. (An abstract class in 
  C++ is a class that contains at least one pure virtual function.) For example, it is 
  impossible to create an instance of a C++ abstract class or a Java interface. Both are 
  used to specify a consistent interface that subclasses will implement. The main 
  difference is that an interface more cleanly represents this concept.
• Java has a streamlined approach to memory allocation. Like C++, it supports the new 
  keyword. However, it does not have delete. Instead, when the last reference to an 
  object is destroyed, the object, itself, is automatically deleted the next time that 
  garbage collection occurs.
• Java "removes" the C++ standard library, replacing it with its own set of API classes. 
  While there is substantial functional similarity, there are significant differences in the 
  names and parameters. Also, since all of the Java API library is object-oriented, and 
  only a portion of the C++ library is, there will be differences in the way library routines 
  are invoked.
• The break and continue statements have been enhanced in Java to accept labels as 
  targets.
• The char type in Java declares 16-bit-wide Unicode characters. This makes them 
  similar to C++'s wchar_t type. The use of Unicode helps ensure portability.
• Java adds the >>> operator, which performs an unsigned right shift.
• In addition to supporting single-line and multiline comments, Java adds a third 
  comment form: the documentation comment. Documentation comments begin with a 
  /** and end with a */.
• Java contains a built-in string type called String. String is somewhat similar to the 
  standard string class type provided by C++. Of course, in C++ string is only available if 
  you include its class declarations in your program. It is not a built-in type.