When The Context Starts

If you wish for a particular method to be invoked when a bean is constructed then you can use the javax.annotation.PostConstruct annotation:

import javax.annotation.PostConstruct; (1)
import javax.inject.Singleton;
@Singleton
public class V8Engine implements Engine {
    private int cylinders = 8;
    private boolean initialized = false; (2)
    public String start() {
        if(!initialized) {
            throw new IllegalStateException("Engine not initialized!");
        }
        return "Starting V8";
    }
    @Override
    public int getCylinders() {
        return cylinders;
    }
    public boolean isIntialized() {
        return this.initialized;
    }
    @PostConstruct (3)
    public void initialize() {
        this.initialized = true;
    }
}

import javax.annotation.PostConstruct (1)
import javax.inject.Singleton
@Singleton
class V8Engine implements Engine {
    int cylinders = 8
    boolean initialized = false (2)
    String start() {
        if(!initialized) throw new IllegalStateException("Engine not initialized!")
        return "Starting V8"
    }
    @PostConstruct (3)
    void initialize() {
        this.initialized = true
    }
}

import javax.annotation.PostConstruct
import javax.inject.Singleton
@Singleton
class V8Engine : Engine {
    override val cylinders = 8
    var isIntialized = false
        private set (2)
    override fun start(): String {
        check(isIntialized) { "Engine not initialized!" }
        return "Starting V8"
    }
    @PostConstruct (3)
    fun initialize() {
        this.isIntialized = true
    }
}