1. Upcasting in java stackoverflow.comIn Java, suppose I have 3 classes, C extends from B which extends from A. And I have one method: |
2. What is the difference between these two ways of casting in Java? stackoverflow.comWhat is the difference between these two ways of casting in Java?
Class#cast(Object) is as follows:
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3. Is it more efficient to cast twice or create new instance stackoverflow.comConsider these 2 pieces of code (you can assume |
4. java casting confusion stackoverflow.comCould anyone please tell me why the following casting is resulting in compile time error: |
5. java.lang.classcastExcption stackoverflow.comI have an array list of objects in my application. |
6. Java - short and casting stackoverflow.comI have the following code snippet. |
7. Remove redundant casts in Java stackoverflow.comI've been generifying some Java code that used lots of casts, and now most of them are redundant and unnecessary. It could be very tedious to inspect all the usages of the ... |
8. Is there a better option for this code? stackoverflow.comAnimal |
9. In Java, is it possible to cast to void (not Void)? stackoverflow.comIs there anything I can put in X, to make the follow work: |
10. How to iterate over the sets in a SetMultimap without a cast? stackoverflow.comI have a |
11. Generating (PKCS12) certificate friendly name with Bouncy Castle in Java stackoverflow.comI am using the bouncycastle library to create certificates and export them as PKCS12 certificate files on a Java webapp. The code on my app to generate the certificate file is the ... |
12. Java casting order stackoverflow.comLet's say I have the following setup a.foo() returns type B.
When ... |
13. Why can't I cast WFSFeatureSource into SimpleFeatureStore? stackoverflow.comIn the GeoTools Javadoc for Transaction (and in a few other places, such as blogs and so forth) they suggest lines like this for performing transactions on the database: |
14. understanding casting in this program stackoverflow.com |
15. Java Casting String to TCPpacket like jpcap stackoverflow.comI have an ecrypted String like [B@1df280b and i would like to change it to a tcppacket header like TCPPacket p=new TCPPacket(int (x4), boolean (x7), int(2)); In fact, i encrypted a packets ... |
16. Why do I need to cast? stackoverflow.comIn the following code snippet, I am not very clear about the usefulness of |
17. Casting in Java stackoverflow.comIf I have class |
18. for-each syntax cast stackoverflow.comCan someone tell me what's going on here? It looks to me like myObj is being cast to String[] so it can be iterated on in the for loop. ... |
19. Code not compiling - casting stackoverflow.comCommented code below are the reasons I think the code is not compiling, is this correct ? |
20. casting coderanch.com |
21. Casting imposssible!! coderanch.comDear Developer... i like the java for it's object oriented feauture.. im shocked that i cant make casting for this issue: Object object; Apple apple; Orange orange; if(condition) { object=apple; } else { object=orange; } my Wish that i can use the object like what the condition applied.. in other words: i want the object to be outer this scope either ... |
22. Casting coderanch.comIs there any way to cast an entire array to the required type, instead of having to loop through and cast each element explicitly e.g. ArrayList array = new ArrayList(); // Add some elements of String type Object[] array = array.toArray(); for (int i = 0; i < array.length; i++) { array[i] = (String) array[i]; } Any help would be appreciated? ... |
23. Doing away with casts coderanch.comOriginally posted by Pho Tek: 1 Repository repository = .. 2 Tree tree = ... 3 4 repository.remove( (Group)tree.getSelection() ); 5 6 class Repository .. 7 public void remove( Group g ).. 8 public void remove( Person p ).. 9 10 class Group extends Node.. 11 12 class Person extends Node.. tree.getSelection() returns the type Object. So I have ... |
24. Casting doubt : Urgent coderanch.comThorough instance of ClassLoader, I am loading a class file as follows : Class comp = loader.loadClass(name); /* comp object represents the class loaded, which is say,dog.class */ Object o = comp.newInstance(); /* Object o gets created succesfully */ /* This displays : " OBJECT O's CLASS TYPE : dog */ System.out.println("OBJECT O's CLASS TYPE : " +o.getClass().getName()); but after this ... |
25. deserialization and casting coderanch.comA simple socket server receives objects of various types through an ObjectInputStream. So all objects received, regardless of their original type are received as type Object. I would like to find the most compact way of handling the input - likely simply by overloaded handling methods - one for each original object type. What's getting in the way is the deserialization ... |
26. casting coderanch.comHey there, 200 in binary as a short (16 bits) is 0000000011001000 when you assign a short to a byte in java you always take the least significant byte. giving 11001000 since java byte is always signed you end up with a negative number (most significant bit is a flag, 0 = pos, 1 = neg) try this code if you ... |
27. casting coderanch.comCharlie: You cannot force an object of junk()to be an object of junksub() even with an explicit cast. For example: Create a class Animal Create class Dog extends Animal You cannot forcibly make any Animal a Dog by explicit casting But a Dog is naturally an Animal (defined in the class hierarchy) I rewrote your code using the example // File: ... |
28. casting coderanch.comIf you are looking for The advantages of Type Casting. Suppose If you want to the value of int data type variable assigned into the short data type variable. You will get an error. Offcourse (In general life) its impossible to store full volume of water filled in a jug into a glass. Whereas we can store the glass water into ... |
29. WHat is Explicite Casting and Implicite Casting coderanch.comCasting is a general form of type conversion. explicit cast: float money = 1.00F; int dollars; dollars = (int) money; (int) is the cast. It tell the compiler to treat the variable money, which is of type float, as if it were of type int when it gets assigned to dollars. After this statement is executed, money will be type float; ... |
30. Casting coderanch.comCasting is done to change the type of some variable. Java is strictly typed language. IF we want to assign the value of... let say int type of variable to the other type for example double or float etc. Suppose all types are cups byte smallest, short larger than byte, int more larger than byte and short and so on........ We ... |
31. casting coderanch.comHi! To convert to a wider primitive you don't have to do anything. Java does that for you! Example: byte b = 4; int i = b; Remember that float is wider then long although float is 32 bit and long is 64 bit. It is legal to do Example: long b = 4L; float i = b; If you do ... |
32. casting coderanch.combyte b=(byte)256; System.out.println("B = " + b); Answer: Since the integer's value (256) is larger than the byte's range (-128 - +127), the result is the remainder of the division of the integer value by the byte's range (256). This is displayed: B = 0 The Answer given states that it should be 127/256? Does someone understand why this is so? ... |
33. y do v need casting coderanch.comBecause Java is a "strongly typed language". Basically that means that when you declare a variable in Java you must name the type of thing that can go in it. And that is the ONLY thing that can go in it. Some languages allow sort of generic variables that can hold an assortment of stuff - but not java. Therefore if ... |
34. Casting up thie hierarchy coderanch.com |
35. Cast coderanch.comThe code compiles because it meets 3 rules for narrowing conversion: 1. The right operand is a constant expression of type byte, char, short, int. 2. The left opereand is of type byte, char, or short. 3. Value is in range of the left opereand. No cast is required if these 3 rules are met. |
36. casting coderanch.comYou don't get a runtime exception if the object is of the subclass type. You've discovered that on your machine, the automatic Graphics object is also a Graphics2D object. Remember, you can refer to an object of the subclass with an identifier that is of the superclass type, and you can also cast the object back down to the subclass (of ... |
37. Tokens, casting, etc coderanch.comI'm using a Stack containing Token objects. Each token has 2 fields, an Object value and an Int priority. My problem is that some of the values are of type double, and I'm having trouble casting them into anything I can use... I pushed the Tokens into the stack with the numbers in String form, since I had to parse a ... |
38. Casting with a String coderanch.comProbably a bad title, but best I could do. OK, suppose you have a class, like GamePiece and then subclasses of that class like Knight, Rook, Queen, King, etc. And suppose you have an array of GamePieces....some of them will be Knights, some Rooks, some Queens, etc. You are going through the array, and you don't know which is which so ... |
39. casting coderanch.com |
40. How can I valid my invalid cast? coderanch.comHi friends, I have an error which says I used invalid cast from int to boolean! but the other side strWork is string and I do not understand what it says? Could you please help me on this? Many thanks, Elahe Error: ========= Invalid cast from int to boolean. if( strWork.compareTo( "0" ) ) { ^ Invalid cast from int to ... |
41. Casting rules coderanch.comThanks. I used the wrapper class and then the toString() method to achieve the result. class casting { public static void main(String[] s) { int x=24; byte b=8; String str = ""; Integer wrapX = new Integer(x); Byte wrapB = new Byte(b); str = wrapX.toString(); str = wrapB.toString(); //overwrite str System.out.println(str); } } |
42. What is your understanding of "Casting" ? coderanch.comFor the following code class Super{ int a = 1; int b = 2; } class Sub extends Super{ int a = 3; int c = 4; } class Foo { public static void main(String argv[]){ Sub sb = new Sub(); Super sp = (Super)sb; System.out.println("sb.a = " + sb.a); System.out.println("sp.a = " + sp.a); } } The result is : ... |
43. Casting to and from Stacks coderanch.comI've got a few questions regarding Stacks and casting to and from them. I've been trying to use stacks to do calulations from strings such as 43+ and 84/2/53+6*- and in the process a few questions about Stacks and casting have popped up. I've been taking the String and extracting each digit and placing it in the Stack as a Character ... |
44. Casting, Narrowing and Widening coderanch.comCould someone kindly tell me if I have this right? I am trying to understand what happens during an assignment statement that involves any of the primitive data types and when a cast is implicit or explicit. byte---short---int---long---float---double char If I move from left to right on the above, am I widening my primitive types? I know that I have to ... |
45. short, forced to cast ? coderanch.comSo my program uses a short and I originally attempted to assign it a value like so: static short zeroLeadsOne = 21845;//0101010101010101 However Java forces me to cast it using the following statement: static short zeroLeadsOne = (short) 21845;//0101010101010101 Can someone help me understand why I'm forced to cast this as I belive the value meets the primitive data type requirements. ... |
46. casting coderanch.comHi people Hope maybe someone could figure this one out. I am trying to write some code that displays the time in seconds to millisecond precision i.e. 1.354. Unfortnatley my code at the moment displays 1.354 seconds as 1354. Could someone let me know how to cast this correctly i have included my code below. public long dt = 0; public ... |
47. use of casting coderanch.comHi All I would like to know what is the use of casting Say if we have Class A with 1 method public void meth1() now i create a child class Class B extends A & add 1 more method public void meth2() now in a main method i create A x = new B(); now i can call only meth1() ... |
48. Reference casting coderanch.comLet's take this example: -Vehicle --Car ---Pinto Let's say you create a new Car: Car myCar = new Car(); You can't go like this: Pinto myPinto = (Pinto)myCar; Because the Car is NOT a Pinto. But you can go like this: Pinto myPinto = new Pinto(); Car myCar = (Car)myPinto; The Pinto loses its functionality as being a Pinto, when put ... |
49. casting String to ? 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. - ... |
50. casting coderanch.comIn the following codes, could someone tell me why I got error when trying to cast Object back to Orange or Apple? How can one cast the object back to its original type? Thank you ======================== import java.util.*; import java.lang.reflect.*; public class test1 { public static void main(String args[]) { List fruits = new ArrayList(); Orange orange = new Orange(); orange.setIt("ORANGE"); ... |
51. Cast from StringBuffer to String coderanch.com |
52. When do you cast coderanch.comThere is a distinction betwee the class of an object and the type of a reference to an object. For example, a reference of type Integer can refer to an Integer object. So can a reference of type Number and a reference of type Object because these are the superclasses of Integer. If I say "Integer I = new Integer(3);", I ... |
53. Casting of Reference coderanch.comAlso, a super class is often a standalone class. Why should it have a subclass' method? A Dog is an Animal, but why should an Animal have to bark? A Cat is an Animal, does that mean an Animal has to miow? Given an unkown Animal how can you make it utter a sound? |
54. Casting coderanch.com |
55. precedence: new, cast, dot, coderanch.comPrecedence tables tell me that "dot" operator has higher precedence than "new" and cast operators. The latter two have same precedence. According to this it makes sense that the following doesn't compile: Object o = new String("Hello2"); // following won't compile // myChar = (String)o.charAt(0); However, I can't explain that why does the following work: char myChar = new String("Hello").charAt(0); It ... |
56. Casting coderanch.com |
57. Casting coderanch.comclass Parent { public void method1() { System.out.println("Parent - Method1"); } } class Child extends Parent { public void method2() { System.out.println("Child - Method2"); } public void method1() { System.out.println("Child - Method1"); } } class Kid extends Parent { public void method3() { System.out.println("Kid - Method3"); } public void method1() { System.out.println("Kid - Method1"); } } class T { public static ... |
58. Casting coderanch.comAssuming that you've missed the "extends Superclass" off the Subclass definition by accident: Yes they are the same. What is happening here ? A new Superclass object is created and referenced by variable "sc" and a second variable "sbc" is created which references a new Subclass object. Two objects and a reference to each of them. Then the assignment results in ... |
59. to cast or not to cast coderanch.comWhat exactly is in the first two character positions? If it's a string like "01" you can substring and then use Integer.parseInt(). If it's something binary like 0x00 0x01 then I'm worried about it making the transition from the message to a String and back to a number. You can try taking a substring and getBytes() and working from there. |
60. Casting issue coderanch.comHi, Welcome to JavaRanch! An array of double is not an array of Objects, because doubles aren't Objects. The only way to convert an array of double into an array of Double (the wrapper class) is to create an entirely new array of the right size and then, in a loop, create a Double for each double value and store it ... |
61. Using Final Keyword & Casting coderanch.com |
62. What happens during casting coderanch.comTo represent the number 40002 in binary requires 16 bits - 1001110001000010. The long data type is 64 bits - hence no "two's complementation". It's a positive integer - 16 bits well and truly fits into 64 bits. The short data type is 16 bits in length, so when the cast takes place, the binary representation does not change. However, since ... |
63. casting confusion coderanch.comHi there!! I was studying Type conversion and casting and wrapper classes. There are a few things I got messed up: 1. type conversion vs wrapper classes... basically whats the difference??? How will I know what to use?? 2. I read a few examples abt casting one user defined class to a different one, if you have a really simple example ... |
64. Doubt in casting coderanch.comHello all, As Iam in starting stage of JAVA ,I got this doubt.Actually tried to point out the reason by myself ,but could not,so taking help from you all. when Iam trying to assign a double variable(which occupies 64 bits) to a var.of type float(which occupies 32 bits) ,compiler is showing error,but when I cast it,it is not showing any error.But,when ... |
65. Casting coderanch.comFor all the numeric primitive types, when you downcast a number (in this case from long to float) it looses its actual value. In this case you are assigning value contained in long ( 64 bit ) number to a float (32 bit )variable. So the last 32 bits are lost and thats why it allows you to downcast in case ... |
66. abt Cast coderanch.com |
67. down casting coderanch.comHiya, 1)I am not sure what you mean by downcasting, can never remember if its up or down. However in your example "downcasting" is only possible between a class and its super class, i.e you can down cast a Dog to an Animal, as it maintains the "IS A" relationship, a Dog IS A Animal. However an Animal IS NOT a ... |
68. multiple casting coderanch.comThere are hundreds of ways to write useless and pointless code in Java. But trying to write a language definition that makes code like "i = i++" illegal because it doesn't do anything and does it in a confusing way, for example, would be extremely difficult. It's better to just write a simple language and let programmers do what they will. ... |
69. About Illegal Casting coderanch.comHello there true believers ! Casting sibling Objects Has nothing to do with polymorphism (as far as I know), and it means Casting between Objects that share a common Parent or Super class, but aren't in line in the same inheritance tree, for example... class Father { } class Son extends Father { } class Daughter extends Father { } In ... |
70. (cast)ing rules coderanch.comWelcome to JavaRanch, Yoogesh Patil. Please don't ask new questions on somebody else's thread. If you write out the bits for 130 in 16 bits, which are the same as a long only with fewer 0s, you get 0000 0000 1000 0010. When you cast to a byte you lose all but the rightmost 8 bits, leaving 1000 0010. In two's ... |
71. casting.. coderanch.comWelcome to JavaRanch. You're declaring a variable named 'e'. The type of 'e' is 'D'. Then you create a new object of type 'E', and cast it to type 'D'. Casting means that you tell the compiler: "I have an object here, and you must pretend that this object is of type D". |
72. Doubt related to casting coderanch.compublic class Foo extends boo { public static void main(String[] args) { boo bObject = new Foo(); Foo fObject= new Foo(); boo bObject1=(boo)fObject;//line of confusion bObject1.abc();//prints in Fooo// } void abc() { System.out.println("in Fooo"); } } class boo{ void abc() { System.out.println("in booo"); } } I am not able to understand that bObject1 is of type boo and it contains a ... |
73. casting coderanch.com"byte b = 27; but only because the compiler automatically narrows the literal value to a byte. In other words, the compiler puts in the cast. The preceding code is identical to the following: byte b = (byte) 27; // Explicitly cast the int literal to a byte" -Kathy 1)but if this is tried, compiler not doing implicit casting. Whats the ... |
74. Casting coderanch.comI am having trouble trying to cast one object into another. I have a compareTo method with argument variable o and I am trying to cast it into a Hexagon object so that I can compare 2 objects by a getArea method I have in the Hexagon class. Hexagon h = (Hexagon) o; not really sure what I need to do ... |
75. casting coderanch.comIam new to Java and Iam facing the following problem. I have a superclass,SuperCl, with subclasses SubCl1,SubCl2 and SubCl3. One of the methods in my project returns me an object of SuperCl.But this objcet is actually an instance of one of the subclasses ie., if I call the method getClass().getName() on the returned objcet it will give me the name of ... |
76. Java Cast with Multiple Arguments coderanch.comFor instance, having this class in mind: public class DevInfo { private String name; private String birthday; private String placeOfBirth; public DevInfo(String name, String birthday, String placeOfBirth) { this.name=name; this.birthday=birthday; this.placeOfBirth=placeOfBirth; } public String getInfo(){ return name + " born on " + birthday + " in " + placeOfBirth; } } How can i properly cast it using Context-Init-Parameters or ... |
77. Casting coderanch.comI have two lines of code as shown below : public class Test1 implements Interface1 Interface1 int1 = (Interface1) new Test1(); Can we call this as downcasting ? Or is casting exclusive only for classes ?The rule in downcasting is that we must explicilty write the cast and the object must be a legitimate instance of the class we are casting ... |
78. Casting coderanch.comHello, Let me see if I can get this right. An up cast is going from the specific towards the general. For example your implementing a method in a class that is further up the hierarchy. A down cast, usually described as a 'cast' is when you convert an object that is below a class to an object that is above ... |
79. Java Casting issue coderanch.com3. public class Redwood extends Tree { 4. public static void main(String[] args) { 5. new Redwood().go(); 6. } 7. void go() { 8. go2(new Tree(), new Redwood()); 9. go2((Redwood) new Tree(), new Redwood()); 10. } 11. void go2(Tree t1, Redwood r1) { 12. Redwood r2 = (Redwood)t1; 13. Tree t2 = (Tree)r1; 14. } 15. } 16. class Tree { ... |
80. Casting coderanch.comA double gives a slightly more accurate representation of rational and irrational numbers because it has more bits dedicated to its precision than a float does, a double has 52 of its 64 to give precision whereas a float only has 23. The rest of the bits are the exponent and the sign bit. when you do (float) 5/3 the result ... |
81. What do You Mean By Casting? coderanch.comNo, the memory allocated for the int is not destroyed. When you cast from int to float (or double), the value of the int is converted to the format for a float or double. Nothing happens to the original int value. When you cast reference types (not primitive types), then not much at all happens. The cast is then just a ... |
82. casting string coderanch.comimport java.util.Vector; public class StringCastDemo { public static void main(String args[]) { String username = "asdf"; String password = "qwer"; Vector v = new Vector(); v.add(username); v.add(password); // String u = v.elementAt(0); Cannot convert from object to String Object u = v.elementAt(0); //Cast not done System.out.println("Username object is : " + u); String uname = (String) v.elementAt(0); // cast allowed String ... |
83. I need a little help with using cast. forums.oracle.comint i = 7; int j = 2; int k = i / j; in this case, k will be 3. but if you type casting i and j as doubles, so instead of 7 it will be 7.0, 2 will be 2.0 double d = (double) i / ( double) j; d gives 3.5 double oops = (double) ( i ... |
84. Cast required here - why? forums.oracle.comThat's crazy. Ok, so when you say it "uses the constant directly" do you mean the it has knowledge of the literal value (These variables are on the stack) without having to go looking at the value of the variable? I understand what you're getting at. It has to go and deduce the value of j each time, unlike the compile-time ... |
85. com.sun.enterprise.naming.SerialContext cannot be cast to org.omg.CORBA.Obj forums.oracle.com |
86. casting issue forums.oracle.comThank you very much for the reply. I have asked the JAN2008 is in Date format. I want to get the last day of the month. And I want to change the whole into 2008-01-31 But in Date type. I tried Calendar calendar=Calendar.getInstance(); calendar.setTime(new Date()); DateFormat validateFormatter1=new SimpleDateFormat("MMMyyyy"); String kursEndDate=validateFormatter1.format(calendar.getTime()); System.out.println("Now after" +kursEndDate); The output is Feb2008. How can I change ... |
87. Casting forums.oracle.comThanks for trying to help.. but I can't use parseInt.. which is what Google gave me as a solution as well.. and I don't initially know the value of the integer so I couldn't use something like int a = new Integer("12").intValue(); -or- int a = Integer.parseInt("12"); anyways. I need to obtain the value from the input in a text field. ... |
88. Casting forums.oracle.comFor an implicit cast, you don't have to write code -- it happens automatically. Implicit casts are when you are putting something smaller into a larger container. It always fits, so no need to cast. An explicit cast happens when you are putting something larger into a smaller container -- so you have to tell Java that you really know what ... |
89. is it possible to cast from short to String forums.oracle.com |
90. how to cast this? forums.oracle.com |
91. Without casting, is there anyother way? forums.oracle.comThe reason why is the following, there is one big panel. I have to change only the one of big panel. And big panel is shared by each version. A version -- requires no change. B version-- requires only the one panel of Big panel needs to be changed. So, I created createTheOnePanel() method return Parent Panel in BigPanel and when ... |
92. for loop need cast - why? forums.oracle.com |
93. Casting issues forums.oracle.comEverything compiles but on runtime i get this error: Exception in thread "main" java.lang.ClassCastException: HourlyEmployee at EmployeeUtilities.getEmployee(EmployeeUtilities.java:453) at Corporation.main(Corporation.java:81) This is the line in corporation that is having the problem - temp=employeeObj.getEmployee(nameToFind,employeeCollection); I understand the error but really don't know how to go about doing this correctly. I have been stuck here for hours now and would appreciate any feedback. |
94. cast forums.oracle.com* That's not a whole class; it's a single method. * "It says unconveritlbe types" is not much more useful than "doesn't work." You didn't provide the relevant code with an indication of which line. (Well, you might have in an earlier post, but I'm not going to scroll back and try to piece it all together.) You didn't paste in ... |
95. To cast or not forums.oracle.comI had to use index = i++ as I'm using the new For loop although I should stick to the old style to store the values into both arrays for simplicity. As studentID is an array of int primitive, I thought that I need to convert the return Integer key from entry.getKey() to int. That's why I use the intValue(). This ... |
96. How to make inverse casting (is it is named so) ? forums.oracle.comRepeat : A extends B B has three doubles (x,y,z) C is an instance of B I can make cast on A : (B) A But I don't know (maybe is a stupid thing but ..) how to pass C to A. A.B =C ; ???? (this not work of course ) Thanks |
97. java auto casting features? forums.oracle.comDo yourself a favour: stop just dumping random questions on the forum endlessly. Learn to a) stay focused on something until you understand it properly and b) do some research on your own. Despite what you may think, just asking endless "what is?" questions here isn't going to help you learn Java |
98. Why up casting? forums.oracle.com |
99. casting forums.oracle.comAn int can be significantly bigger than 48. If it's big enough, it's bigger than will fit in a char. Thus assigning an int variable to a char might not fit, so the compiler thinks it might be a mistake. By casting, you're telling the compiler that you know about it and it's OK. I guess the compiler is smart enough ... |
100. unable to cast from Node to Element forums.oracle.comcan any one plz write an example code http://www.catb.org/~esr/faqs/smart-questions.html#writewell How To Ask Questions The Smart Way Eric Steven Raymond Rick Moen Write in clear, grammatical, correctly-spelled language We've found by experience that people who are careless and sloppy writers are usually also careless and sloppy at thinking and coding (often enough to bet on, anyway). Answering questions for careless and sloppy ... |