Downcast « cast « Java Data Type Q&A

1. Downcasting in Java

Upcasting is allowed in Java, however downcasting gives a compile error. The compile error can be removed by adding a cast but would anyway break at the runtime. In this case ...

2. Forced Downcasting in Java

I want to force a downcast on a object what can't be down casted and was wondering what the right approach would be. The use case is that I have a list ...

3. Detect Object type then cast it accordingly?

My method takes as input an Object. How do i determine it's type, then cast it accordingly? So for example: binarySearch( Object o ); Inside the binarySearch method, i need a way to ...

4. Why can't I downcast this object in Java?

I have this method:

    private Message getMessage(DataInputStream in) throws IOException {
    CommandEnum caption = CommandEnum.valueOf(in.readUTF());
    BasicMessage inputMessage;
    if (caption.equals(CommandEnum.BEGIN) ...

5. Use Method by Real Type

I learned that I can use the real type of a Object to define which Method is used, such like this:

Object foo = new String("hello");

void bla(String x){
void bla(Integer x){
Now it should ...