Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

public class Employee {

// Class-level: tracks total instance count
    private static int instanceCount = 0;

// Instance fields
    private final int    id;          // assigned at construction, never changes
    private       String name;
    private       String department;
    private       double salary;

// Primary constructor
    public Employee(String name, String department, double salary) {
        if (salary < 0) throw new IllegalArgumentException("Salary cannot be negative");
        this.id         = ++instanceCount;
        this.name       = name;
        this.department = department;
        this.salary     = salary;
    }

// Delegating constructor (calls primary constructor)
    public Employee(String name, String department) {
        this(name, department, 0.0); // new hire with no salary yet
    }

// Static factory method (named constructor)
    public static Employee intern(String name) {
        return new Employee(name, "Internship", 15.0);
    }

// Getters
    public int    getId()         { return id; }
    public String getName()       { return name; }
    public String getDepartment() { return department; }
    public double getSalary()     { return salary; }

// Setters with validation
    public void setName(String name) {
        if (name == null || name.isBlank()) throw new IllegalArgumentException("Name required");
        this.name = name;
    }
    public void setSalary(double salary) {
        if (salary < 0) throw new IllegalArgumentException("Salary cannot be negative");
        this.salary = salary;
    }

// Static getter for class-level field
    public static int getInstanceCount() { return instanceCount; }

@Override public String toString() {
        return String.format("Employee{id=%d, name='%s', dept='%s', salary=%.2f}",
            id, name, department, salary);
    }

public static void main(String[] args) {
        Employee e1 = new Employee("Alice", "Engineering", 90_000);
        Employee e2 = new Employee("Bob", "Marketing");
        Employee e3 = Employee.intern("Carol");

System.out.println(e1);
        System.out.println(e2);
        System.out.println(e3);
        System.out.println("Total employees created: " + Employee.getInstanceCount());

e2.setSalary(65_000);
        System.out.println("After salary update: " + e2);
    }
}