Classes and Objects in Java

Fields, methods, constructors, access modifiers and the static keyword.

Easy

public class Resistor {
    private final double ohms;                 // field

    public Resistor(double ohms) {             // constructor
        this.ohms = ohms;
    }

    public double current(double volts) {     // method
        return volts / ohms;
    }

    public static double series(double a, double b) { return a + b; }   // belongs to the class
}

Access modifiers: private (this class), package-private (default), protected (subclasses), public (everyone). Use getters/setters instead of public fields.

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