Sunday, 15 May 2011

Differences between methods and constructors.

  • There is no return type given in a constructor signature (header). The value is this object itself so there is no need to indicate a return value.
  • There is no return statement in the body of the constructor.
  • The first line of a constructor must either be a call on another constructor in the same class (using this), or a call on the superclass constructor (using super). If the first line is neither of these, the compiler automatically inserts a call to the parameterless super class constructor.
These differences in syntax between a constructor and method are sometimes hard to see when looking at the source. It would have been better to have had a keyword to clearly mark constructors as some languages do.

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