Java vs. C#

Question 1

Determine whether a variable is castable to another.

Answer 1

Java: instanceOf
Object h = new Object();
h instanceof Object -> True
C#: is 
Object h = new Object()l
h is Object -> True

Question 2

Call a class’s base class method / member

Answer 2

Java: 
public MyClass( int a ) 
{
super( a );
}
C#: 
public MyClass( int a ) : base( a )
{
}

Question 3

Lock an expression / object to make it thread-safe

Answer 3

Java: synchronized( x )

C#: lock( x )

Question 4

Create a scope to avoid name collisions, group like classes, etc.

Answer 4

C#: namespace

Java: package