object « cast « Java Data Type Q&A
1. Java: Why can't I cast this to an Object? stackoverflow.comThis is bizarre... I thought every object in java had Object as an ancestor.
I have a |
2. Type casting from an Object stackoverflow.comI have some code in Java as follows: |
3. Casting an object's class stackoverflow.comMy previous OOP experience has been with Objective-C (which is dynamically typed), however, I am now learning Java. I want to iterate over an ArrayList of objects and perform a certain ... |
4. Java rules for casting stackoverflow.comWhen can a certain object be cast into another object? Does the casted object have to be a subtype of the other object? I'm trying to figure out the ... |
5. Stack Calculator: Trouble evaluating postfix expression because of casting issue stackoverflow.comI'm working on a homework assignment that asks me to create a calculator that changes the expression given to it from infix to postfix to then evaluate. I must do so ... |
6. Making custom object convertible stackoverflow.comIn java is it possible for me to design my own class to be convertible(or castable?) to a primitive type? For example, if I have: |
7. Casting objects in Java stackoverflow.comI'm confused about what it means to cast objects in Java. Say you have... |
8. Doubts about object Casting stackoverflow.com
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9. How to prevent an Object being cast to a String automatically stackoverflow.comI have a class that looks like the following: |
10. Type cast from Java.Lang.Object to native CLR type in MonoDroid stackoverflow.comHow to cast Java.Lang.Object to some native type? Example: ListView adapter contains instances of native type Message. When i am trying to get SelectedItem from ListView it returns instance of Message type casted ... |
11. casting object to String[] object..? stackoverflow.comAssume the following scenario. i call a method like this |
12. casting in an object based on an incoming string stackoverflow.comCan this be done in Java |
13. How to determine and cast to specific object of composite while using it? stackoverflow.comI would like to have a composite structure which is build from JSON. Each element can has only one type of children - so a group can contain only groups or ... |
14. Java method for objects cast possibility stackoverflow.comIs is possible to check whether given Object item can be casted to some class? Is there any method which doesn't throw an exception? |
15. casting String to SecretKey object coderanch.com |
16. Casting Object[] into String[] coderanch.comMy question starts with the toArray() method of the Collection - from this I get an Object[] back. However I know that each of the elements in the Collection is a String object, so I figured the obvious thing to do would be to cast it so: String[] strings = (String[]) collection.toArray(); Which as I quickly discovered doesn't work, giving a ... |
17. An elegant way to cast object types coderanch.comI am working on a project that receives an object of the base class. There are several inherted class(es). There are timing issues(this is a packet sniffer) that necessitate collecting the objects as its base class. Is there a good way to cast the object types. Right now I just have a method for each subclass type that casts it and ... |
18. casting Objects coderanch.com |
19. When can I cast one object to another object? coderanch.comTo cast, the types must be related and/or compatible. You can cast a parent object to a child object ( ChildObj = (ChildClass)ParentObj ; ) because they are related. You can cast between primitives ( float f = 1.5; int i = (int)f ; ) when they are compatible. You cast when you have a type that you need to be ... |
20. Object Casting help coderanch.comWhen you downcast, what is really happening here: SubClassRef = (Subclass)SuperClassRef; Isn't the compiler and VM just checking to see if the cast rules are being followed? Many people make the analogy to Primitive casting arguing that since the Primitive variable will refer to a new value in a widening or narrowing conversion, a reference variable will likewise refer to new ... |
21. casting objects coderanch.comthose are pretty broad questions, so it's unlikely you'll get a complete answer in one session. You'll have to study this. Basically, casting is about converting variables from one type to another, related type. There are rules that govern casting, but if you learn the underlying concepts you won't have to just memorize a bunch of static casting rules. The basic ... |
22. Object referernce casting coderanch.comclass Base {} class Sub extends Base {} public class CEx { public static void main (String[] args) { Base b = new Base(); Sub s = new Sub(); // b = s; // works // s = b; // incompatible types-Error when compiling s = (Sub)b; // Class Cast Exception Runtime Error } } Hello, I have problems to understand ... |
23. Casting Object[] to String[] coderanch.comThe soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - ... |
24. Object Casting - Wyh is "i = 0" coderanch.comHello, please check out the code as follows. Why is i=0? Thomas class Top { public Top() {setvalue();} int i; // private void setvalue() protected void setvalue() { i = 2; System.out.println("Top i =" + i); } protected int getvalue() {return i;} } class Bottom extends Top { int j; public Bottom() {setvalue();} // private void setvalue() protected void setvalue() { ... |
25. Object Casting - Wyh is "i = 0" coderanch.comHello, please check out the code as follows. Why is i=0? Thomas class Top { public Top() { setvalue(); } int i; // private void setvalue() protected void setvalue() { i = 2; System.out.println("Top i =" + i); } protected int getvalue() { return i; } } class Bottom extends Top { int j; public Bottom() { setvalue(); } // private ... |
26. Rules on Casting Objects coderanch.com |
27. downward casting of objects coderanch.comA cast can never change the type of an object; it just tells the compiler something that it doesn't know. If you have a class Animal and two subclasses Cat and Dog, then you can cast a variable of type Animal to type Cat if, and only if, that variable actually contains a Cat (or null, I suppose, to be complete.) ... |
28. Hashtables, objects & casting coderanch.comHello jolly-javaranchers! My need is to get a Big Decimal value out of a Hashtable entry. I was gonna ask how, but in the process of "trying it" I found two ways which both work as needed. public class testStuff { static Hashtable myHashtable = new Hashtable(); static String srule1 = null; static int irule1 = 0; static BigDecimal bdrule1 = ... |
29. is it possible to cast a string to class or object coderanch.comCasting is for magicians, not programmers. In Java, casting doesn't actually change objects, ever, or create new ones*. It just provides you with a different view of the same object. E.g., if I do: Object o=(Object)"hello"; then I've got an Object view of that string. I now can't ask it how long it is, etc., because Objects don't have length. String ... |
30. Type cast to Class Object coderanch.comThe soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - ... |
31. Casting, objects, and wrappers coderanch.com |
32. casting objects? coderanch.comI hope this is an easier question to deal with. I am trying to pass a reference to a character object (lch) to a constructor for a different type object (MyList). Please see below. The StringEditor constructor receives two string objects StringEditor(String left, String right) and converts the characters of the string objects to an array of characters and then converts ... |
33. Is there a way to generate a .class object from Class, without hardcoding the cast? coderanch.comHere's my problem: Right now, I'm able to read in the name of a class as a String (i.e., com.blah.blah.blah,XXX) from a .properties file, and convert it to a Class instance via Class.forName(). I've got a utility class that has a method that will generate an object of a specified class (the signature is |
34. how to cast the Object that is recieved when used urlcon.getContent() coderanch.com |
35. Object casting coderanch.com |
36. Object type casting coderanch.comHi, I am unable to understand the term Object typecasting. Whatever I understood, I am depicting here...Please take a look. I am not sure whether Am I correct or not? Let see we have Car as superclass... public class Car{ } public class Ford extends Car{ public String fordMethod(){ return "Ford Method."; } } public class Honda extends Car{ public String ... |
37. Casting an Object to a Class coderanch.com |
38. Casting of Object[] to Animal[] fails coderanch.comHi Casting of Object[] to Animal[] fails while the Object[] array contains only Animal objects when i use a for loop to add each Animal out of the Object[] array to the Animal[] array it works.. but like stated just trying to cast it in one line of code (Animal[]) fails why is that? |
39. Cast Object to Object[] coderanch.comI have an old api that returns a big O Object that is really an array of primitive types. I would like to get that Object into an Object array so that I can convert it to a List |
40. A question about casting from Object[] coderanch.comA question about casting from Object[] (Java in General forum at JavaRanch) A friendly place for programming greenhorns! Register / Login Java Forums Java Java in General A question about casting from Object[] Post by: Derik Davenport, Greenhorn on Aug 01, 2011 19:13:27 Suppose I have a Deivce that contains Widget(field) and that Widgets have two methods getPartsList() and ... |
41. Object cast in Prototype pattern coderanch.comI just go through the prototype pattern with a shallow clone implementation,code as bellow: class Product implements Cloneable{ int[] data = {1,2,3,4}; public Object Clone(){ try { return super.clone(); } catch (CloneNotSupportedException e) { return null; } } } public class Test { public static void main(String[] args){ Product p1 = new Product(); System.out.println(p1.data.toString()); Product p2 = (Product)p1.Clone(); System.out.println(p2.data.toString()); } } ... |
42. Casting Object to another type java-forums.orgpublic class MyCollection |
43. [Ljava.lang.Object; cannot be cast to domain.Customer java-forums.orgHi guys, I am new to Java, working on my 2nd class. I have a project where I use hibernate to read in/write into a DB. I use Net beans 6.9.1. I have a customer object wiht the following fields. private int id; private String name = null; public Task task = null; public List |
44. Cast object to custom class problem java-forums.orgThanks for the replies. 1. Yes. I have a bad habit when it comes to naming conventions. I refactored all of those appropriately. 2. I haven't. They seem interesting... but to my untrained eye it appears it's a way to limit the information passed to an object, which is against what I'd like to do here. I want many different types ... |
45. Object Casting, please help java-forums.orgI am learning Java for the first time, and the only problem I am having right now is understanding object casting. Here is a quick example that does not work and I do not understand why: class A { } class B extends A { } class ObjectCaster { public static void main(String[] arguments) { A a = new A(); B ... |
46. How many objects are made if i do Downward Casting ? forums.oracle.comWhat do you mean? How are what impelmented? e and m do not refer to variables and functions. They refer to an object. I got confused when you posted-- They refer to an Object. But Objects store the addresses of instance variables so that they can point to them. They store the addresses in the form of a tree. Primitive data ... |
47. Casting an object forums.oracle.comIs there nothing that regulates conversation on this forum? This is all getting very scary. Guys, please, please take it easy. If we were all gurus, then there would be no need for this forum. I like to believe that this is a learning environment, not the one in which to trade insults. Enough of this, I beg all of you. ... |
48. Casting Object forums.oracle.comLook, i'd like to say a very big sorry for the outbursts that have been caused within this forum from myself and others. Not here to start a verbal fight. Yes i am new to Java, and want to learn a lot more. Maybe my postings do prevail to be somewhat 'beggin'for people do give me code...but that is not what ... |
49. Casting Objects forums.oracle.com |
50. Casting objects question forums.oracle.com#1 use format for code when posting pls. #2 this is a basic understanding of object inheritance. This is also why overriding a method should be done carefully. #3 you should never use a static method from an instance but only like this SuperClass.staticMethod(); Now, the answer to your question is that when you are SuperClass the only static method available ... |
51. Casting Objects - Can someone explain why Casting Objects are used? forums.oracle.com***** By the way, the following will not work since you cant cast an employee to visePresident. Why? The cast to VicePresident says 'veep' can now access the getPresidentsAttention() function. However, an employee object does NOT have a getPresidentsAttention() function! When veep attempts to call that function, it will fail (or more likely, not even compile): VicePresident veep = (VicePresident)emp; //must ... |
52. When should object casting be used? forums.oracle.com |
53. Object Casting forums.oracle.com |
54. Casting Object using imported class forums.oracle.comYeah i figured it out. The object that was serialized was made in a different project and was contained in a package called "main". In my other project When i was running that method with the "Test" class in the same package as the method, it was, coincidently in the "main" package and when i moved it to my "test" package ... |
55. Casting of objects forums.oracle.comHi everybody, I built class her name Artist and more 3 classes that inherited from Artist(signer,writer and painter) and in Tester (this is my main) I tried to do: ((Singer)artist1).singerPrint(); singerPrint it method of Signer class (that inherited from Artist) when I executed it I got error that this cast is not allow. so my question is: why it is not ... |
56. Problems casting an object from a combo box forums.oracle.comedi2 wrote: I send the combo box as a parameter to a procedure which adds the information from the database, and yes the comboboxes are editable. This is the only object I'm having problems with. I have filled other combo boxes the same way and it works just fine. I'm going to predict that we'll not be able to help you ... |
57. What is the difference between casting implicitly and assigning object? forums.oracle.com2. For casting, try to compile public class ProductAppCast { public static void main(String args[]) { Book b = new Book(); b.setCode("java"); b.setDescription("Murach's Beginning Java 2"); b.setPrice(49.50); b.setAuthor("Andrea Steelman"); // implicitly casting b to p Product p = b; p.setDescription("test"); p.setAuthor("test"); // display the output System.out.println(); if (p != null) System.out.println(p.toString()); else System.out.println("No product matches this product code.\n"); System.out.println("Product count: " ... |
58. Casting an Object forums.oracle.comHaigh a chairde, Fadhb beag agam... small problem, I'm implementing a login system using mysql. Basicly, i have a table of user and password pairs with an id and a logged-in flag. With simple logic, that works, if the user and password pair is correct, then the flag is set to true and the userid is returned for reference. I have ... |
59. Object Type Casting forums.oracle.com |
60. java.lang.Object finding what it can be cast to. forums.oracle.com |
61. casting an object[] to a string[] forums.oracle.comI am having trouble casting the the object[] returned by diagnostics.toArray() to a string[]. Here is my code that i am receiving the error on: ArrayList |
62. Cast Object type.... forums.oracle.comYou can't. Java is not magic. You cannot just "convert" any type to any other type. If it makes sense to cast, you do it at compile-time. If you don't know the types until runtime, your code can only invoke methods on the object by reflection anyway, in which case no casting is necessary What is it you're actually trying to ... |
63. Object Casting forums.oracle.com |
64. casting with Class.cast(Object)?? forums.oracle.com |
I am helping a friend from 1st year to prepare his exam on java.
The teacher asked them to create a method that can cast a Musicians ...