Java is programming language that designed to execute on the Java platform (Java Runtime Environment (JRE)). 

The runtime environment includes the Java Virtual Machine (JVM) as well as a common set of libraries. 

C# is designed to execute on the Common Language Runtime (CLR).



C# allows the programmer to create user-defined value types, using the struct keyword. 



C# allows use of pointers and corresponding pointer arithmetic

Enumerations in C# are derived from a primitive integer type (8, 16, 32, or 64 bit)
Enumerations in Java, on the other hand, are full objects