Want run c and java programme into .net and vice verse.

C/C++ can be run in .NET environment, using UnManaged code concept as:

[DllImport("user32.dll")]
public static extern int CMessageBox(int h,
            [MarshalAs(UnmanagedType.LPStr)]string m,
            [MarshalAs(UnmanagedType.LPStr)]string c,
            int type);

public static int Main(string args [])
{
    CMessageBox(0, "Hello World!", "My Message Box", 0);
    return 0;
}

Java code can be run in .NET and vice versa using few product like JNBridege http://www.jnbridge.com/[^] and OpenJDK.