I switched from C++ to Java and have a problem with nested classes. I would like to initiate an instance of a subclass in the constructor of the superclass. I tried it like this, but it seems to be wrong.
public class Aircraft {
public class LandingGear {
}
public Aircraft() {
Aircraft.LandingGear myLandingGear = this.new LandingGear();
}
}
The idea is that every instance of the class Aircraft has an instance "myLandingGear" of the subclass LandingGear.
For this use case, your nested class should be static (if it's going to be nested at all), and then you just use a simple new:
public class Aircraft {
public static class LandingGear {
// ----^
}
public Aircraft() {
Aircraft.LandingGear myLandingGear = new LandingGear();
// --------------------------------------^^^^
}
}
When it's not static, it's an inner class, which from your description isn't what you want. More on nested classes in this Java tutorial.
But unless there's a really good reason for LandingGear to be nested inside Aircraft, consider making it a peer instead.
Every Aircraft will have a LandingGear
public class Aircraft {
private LandingGear myLandingGear;
public Aircraft() {
myLandingGear = new LandingGear();
}
public LandingGear getLandingGear() {
return this.myLandingGear;
}
}
public class Aircraft {
public class LandingGear {
public static void m1()
{
//Your code snipet
}
}
public Aircraft() {
LandingGear.m1();
}
}
has an instance of. This doesn't need to be an inner class. But Aircraft need to have a variable of this class[<>]toolbar button) are for runnable in-browser examples using JavaScript, HTML, and/or CSS, not Java. For Java, just use a simple code block (the{}toolbar button).