C# FAQ: What is the difference between calling base class constructors in CSharp and Java

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What is the difference between calling base class constructors in C# and Java?

Both the C# and Java languages provide ways to call one constructor from another in a process called constructor chaining. This reduces constructor code duplication.

The following are C# and Java examples of constructor chaining with custom exceptions:

using System; 
 
class CSharpException: Exception
{
   private int errorNumber; 
 
   public CSharpException (string errorMessage): 
      this (errorMessage, null, 99) {}
 
   public CSharpException (string errorMessage, 
      Exception nestedException):
      this(errorMessage, nestedException, 99) {}
 
   public CSharpException (string errorMessage, 
      Exception nestedException, 
      int errorNumber): 
      base (errorMessage, nestedException)
   {
      this.errorNumber = errorNumber;   
   }
 
}

class JavaException extends Exception
{
   private int errorNumber; 
    
   public JavaException (String errorMessage)
   {
      this (errorMessage, null, 99); 
   }
 
   public JavaException (String errorMessage, 
      Exception nestedException)
   {
      this (errorMessage, nestedException, 99); 
   }
 
   public JavaException (String errorMessage,
      Exception nestedException, 
      int errorNumber)
   {
      super (errorMessage, nestedException); 
      this.errorNumber = errorNumber;     
   }
}

See also

• C# for Java Developers
• Does C# support custom exceptions?
• What is the difference between C# and Java constructor chaining?
• What is the difference between calling base class constructors in C# and Java?
• Are C# constructors inherited?
• How can one constructor call another?
• Are constructors the same in C++ and C#?
• Are destructors the same in C++ and C#?
• How call a virtual method from a constructor or destructor?
• How do destructors work in C#?
• How enforce constructor correctness in C#?
• How make a C# destructor virtual?
• What are the differences between C# and Java constructors?
• What are the differences between C# finalizers and Java destructors?
• What is the syntax for calling an overloaded constructor from within a constructor?
• Why must struct constructors have at least one argument?