How do we initialize an array within object parameters in java?

You can initialize the array variable which is declared inside the class just like any other value, either using constructor or, using the setter method.

Example

In the following Java example, we are declaring an instance variable of array type and initializing it from the constructor.

public class Student {
   String name;
   int age;
   String subs[];
   Student(String name, int age, String subs[]){
   this.name = name;
   this.age = age;
   this.subs = subs;
}
public void display() {
   System.out.println("Name: "+this.name);
   System.out.println("Age :"+this.age);
   System.out.print("Subjects: ");
   for(int i = 0; i < subs.length; i++) {
      System.out.print(subs[i]+" ");
   }
}
public static void main(String args[]) {
   String subs[] = {"Mathematics", "English", "Science", "Social"};
   Student obj = new Student("Krishna", 25, subs);
   obj.display();
   }
}

Output

Name: Krishna
Age :25
Subjects: Mathematics English Science Social

Example2

public class Student {
   String name;
   int age;
   String subs[];
   public void setName(String name) {
      this.name = name;
   }
   public void setAge(int age) {
      this.age = age;
   }
   public void setSubs(String[] subs) {
      this.subs = subs;
   }
   public void display() {
      System.out.println("Name: "+this.name);
      System.out.println("Age :"+this.age);
      System.out.print("Subjects: ");
      for(int i = 0; i < subs.length; i++) {
         System.out.print(subs[i]+" ");
      }
   }
   public static void main(String args[]) {
      String subs[] = {"Mathematics", "English", "Science", "Social"};
      Student obj = new Student();
      obj.setName("Krishna");
      obj.setAge(25);
      obj.setSubs(subs);
      obj.display();
   }
}

Output

Name: Krishna
Age :25
Subjects: Mathematics English Science Social