如何修复IllegalStateException？

public class Example {
    private Resource resource;

    public void init() {
        this.resource = new Resource();
    }

    public void useResource() {
        if (resource == null) {
            throw new IllegalStateException("Resource not initialized");
        }
        // 使用资源的代码
    }
}

public class StatefulObject {
    private boolean initialized = false;

    public void initialize() {
        // 初始化逻辑
        initialized = true;
    }

    public void performAction() {
        if (!initialized) {
            throw new IllegalStateException("Object not initialized");
        }
        // 执行操作的代码
    }
}

public class LifecycleManager {
    private Thread workerThread;
    private volatile boolean isRunning = false;

    public void start() {
        if (isRunning) {
            throw new IllegalStateException("Thread already running");
        }
        workerThread = new Thread(() -> {
            isRunning = true;
            // 工作逻辑
        });
        workerThread.start();
    }

    public void stop() {
        if (!isRunning) {
            throw new IllegalStateException("Thread not running");
        }
        workerThread.interrupt();
        isRunning = false;
    }
}

public void criticalMethod() {
    assert isReady() : "Object not in a valid state";
    // 关键逻辑
}

private boolean isReady() {
    // 检查对象状态的逻辑
    return true; // 或 false
}