- CourseSession
- Enrolling Students
- int
- Initialization
- Default Constructors
- Suites
- The SDK and java.util.ArrayList
- Adding Objects
- Incremental Refactoring
- Objects in Memory
- Packages and the import Statement
- The java.lang Package
- The Default Package and the package Statement
- The setUp Method
- More Refactoring
- Class Constants
- Dates
- Overloaded Constructors
- Deprecation Warnings
- Refactoring
- Creating Dates with Calendar
- Comments
- Javadoc Comments
- Exercises
This chapter is from the book
This chapter is from the book
This chapter is from the book
Default Constructors
You may have noted that neither of the test classes, StudentTest and Course-SessionTest, contains a constructor. Often you will not need to explicitly initialize anything, so the Java compiler does not require you to define a constructor. If you do not define any constructors in a class, [1] Java provides a default, no-argument constructor. For StudentTest, as an example, it is as if you had coded an empty constructor:
class StudentTest extends junit.framework.TestCase {
StudentTest() {
}
...
}
The use of default constructors also implies that Java views constructors as essential elements to a class. A constructor is required in order for Java to initialize a class, even if the constructor contains no additional initialization code. If you don't supply a constructor, the Java compiler puts it there for you.