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Java Java Objects Meet Objects Final

johnny lawma
johnny lawma
3,298 Points
Posted by johnny lawma
johnny lawma
3,298 Points

can any one explain what is happening in this code? kind of confuse. (java constructor )

class PezDispenser {
  final private  String characterName;

  public PezDispenser(String characterName) {
      this.characterName = characterName;

  }

  public String getCharacterName() {
    return characterName;
  }
}

i'm little confuse with those characterName.

2 Answers

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

I can relate! I don't like to use the same name for variables and parameters for exactly this reason. But that's what we have here. Now what if we just give the constructor parameter a different name:

  public PezDispenser(String nameToSet) {  // renamed parameter
      characterName = nameToSet;           // don't need "this" when names are different
  }

Does that help it make more sense?

Zhaopeng Wang
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Zhaopeng Wang
Full Stack JavaScript Techdegree Graduate 32,210 Points
Zhaopeng Wang
.a{fill-rule:evenodd;}techdegree seal-36
Zhaopeng Wang
Full Stack JavaScript Techdegree Graduate 32,210 Points 
 /* fields */ 
  String firstName; 
  String lastName;
  String age;

Those fields define what a student should have.

  • the following is called the constructor, 
Student(String someFirstName, String someLastName, String someAge) {
    this.firstName= someFirstName;
    this.lastName= someLastName;
    this.age= someAge;
}
  • constructor defines how you will be instantiate a new student.

Therefore, you can define a new student by 

Student newStudent = new Student("John","Smith","25");
Zhaopeng Wang
seal-mask
PLUS
.a{fill-rule:evenodd;}techdegree seal-36
Zhaopeng Wang
Full Stack JavaScript Techdegree Graduate 32,210 Points
Zhaopeng Wang
.a{fill-rule:evenodd;}techdegree seal-36
Zhaopeng Wang
Full Stack JavaScript Techdegree Graduate 32,210 Points
  • characterName is a field defined for class PezDispenser.
  • PezDispenser has different looks, just as Lego Toys, you can have Iron Man, SpiderMan and etc. as the look of the PezDispenser.
  • In terms of Java, the characterName is referred as "Fields" within the class "PezDispenser"
  • For example, we can define a class called Student.java. And a student has firstName, lastName and age. You you can define 
class Student{

  /* fields */ 
  String firstName; 
  String lastName;
  String age;

  /* constructor */
  Student(String first, String last, String age) {
    this.firstName= first;
    this.lastName= last;
    this.age= age;
  }      

  /* accessors */
  String getName() { return this.firstName+" "+this.lastName; }

}
johnny lawma
johnny lawma
3,298 Points
johnny lawma
johnny lawma
3,298 Points 
/* why do make a new String if the value is store in the field */

Student(String first, String last, String age) {
    this.firstName= first;
    this.lastName= last;
    this.age= age;
}

why do we declare a new student string name, last and age,? if the value is store in the field.