try {
    // 可能抛出IOException的代码
    throw new IOException("文件错误");
} catch (NullPointerException e) {  // 捕获的是NPE，不是IOException
    System.out.println("捕获到异常: " + e.getMessage());
}

try {
    // 一些代码
} catch (Exception e) {
    throw new RuntimeException("在catch块中抛出新异常");  // 这个异常不会被外层catch捕获
}

new Thread(() -> {
    throw new RuntimeException("线程异常");  // 这个异常不会被主线程捕获
}).start();

Thread thread = new Thread(() -> {
    throw new RuntimeException("线程异常");
});
thread.setUncaughtExceptionHandler((t, e) -> {
    System.out.println("捕获到线程异常: " + e.getMessage());
});
thread.start();

CompletableFuture.runAsync(() -> {
    throw new RuntimeException("异步异常");  // 这个异常不会被主线程捕获
});

CompletableFuture.runAsync(() -> {
    throw new RuntimeException("异步异常");
}).exceptionally(e -> {
    System.out.println("捕获到异步异常: " + e.getMessage());
    return null;
});

try {
    throw new OutOfMemoryError("内存不足");  // Error不是Exception的子类
} catch (Exception e) {
    System.out.println("不会执行到这里");
}

try {
    throw new OutOfMemoryError("内存不足");
} catch (Throwable t) {
    System.out.println("捕获到Throwable: " + t.getMessage());
}

try {
    throw new Exception("测试异常");
} catch (Exception e) {
    // 没有做任何处理，相当于"吞掉"了异常
}

try {
    throw new Exception("测试异常");
} catch (Exception e) {
    e.printStackTrace();  // 至少打印堆栈
    // 或者使用日志框架记录
}