In C++ there is concept of pointers for memory management 
but there is garbage collecor in Java which automatically 
allocates and frees memory after the particular scope in 
the code...In C++ it supports concept of multiple 
inheritance but for java instead of multiple inheritance 
there is concept of interface...

in java we must need atleast one class to define our code

in java we must need atleast one class to define our 
code...but in c++ we can also define it without a class..

Java is Pure Object Oriented while C++ is not .

c++ is an object oriented language. but java is pure object 
oriented language.in java all properties are based on 
classes and objects.but in c++ we can write and execute the
program with out using class.

In c++,there is destructor but in java there is no 
destructor.
c++ programs are faster than java programs.
c++ supports multiple inheritance whereas java does not.
in c++ , we can write programs without classes but in java 
we have to use classes .

Java is interpreted. This means that java source code is
compiled once, but it has to be interpreted by the JVM (Java
Virtual Machine) everytime the programme is executed. On the
other hand, C++ is not. C++ source code will compile once,
but it is NOT interpreted everytime the programme runs,
because C++ code is converted directly to machine language
instructions (in the machine that the C++ programme was
compiled). This is the reason why C++ is NOT portable.

Java is portable. This means that any Java programme can be
executed in any machine, provided that it has a JVM. C++
applications can only be executed in the machine in which
they were created (or in some cases, in similar machines
e.g. a C++ application that was writen in a computer under
the Windows XP Operating System, it will probably run in
other computers with Windows XP and maybe in computers with
other Windows versions, but certainly not in a cell phone).

That's why Java programmes are slower. They have to be
interpreted at runtime and this yields some overhead. This
is the efficiency - portability trade-off. Java applications
are portable, but C++ applications are executed faster.

Finally, there are some ways to overcome this trade-off from
both languages' point of view, but this is not the subject
of the question.

Java is simply different from C++.Because it do some 
modification to c++ then after it publish..So there are 6 
major difference here i can explain.These are 

1-java doesn't support predessors.Where as C++ support this.
2-Java doesnot support Multiple inheritance however it use 
this by using interface.
3-Java doesn't contain any pointer value.
4-Java have no template class.
5-Java doesn't contain any datatype such as 
struct,enum,union.
6-Java have no Go to keyword.

Above these points are not supported by java , but 
supported by c++.So these are the difference between java 
and c++.