Dereferencing Error In Java
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Java Dereferencing Null Pointer
of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up “int cannot be dereferenced” in Java up vote 9 down vote favorite 2 I'm fairly new to
Dereferencing C
Java and I'm using BlueJ. I keep getting this "Int cannot be dereferenced" error when trying to compile and I'm not sure what the problem is. The error is specifically happening in my if statement at the bottom, where it says "equals" is an error and "int cannot be dereferenced." Hope to get some assistance as I have no idea what to do. Thank you in advance! public class Catalog { private int cannot be dereferenced java Item[] list; private int size; // Construct an empty catalog with the specified capacity. public Catalog(int max) { list = new Item[max]; size = 0; } // Insert a new item into the catalog. // Throw a CatalogFull exception if the catalog is full. public void insert(Item obj) throws CatalogFull { if (list.length == size) { throw new CatalogFull(); } list[size] = obj; ++size; } // Search the catalog for the item whose item number // is the parameter id. Return the matching object // if the search succeeds. Throw an ItemNotFound // exception if the search fails. public Item find(int id) throws ItemNotFound { for (int pos = 0; pos < size; ++pos){ if (id.equals(list[pos].getItemNumber())){ //Getting error on "equals" return list[pos]; } else { throw new ItemNotFound(); } } } } java int bluej share|improve this question edited Jul 19 at 0:13 Sotirios Delimanolis 154k25246361 asked Oct 1 '13 at 6:08 BBladem83 183129 2 You're trying to using a int where an Integer, Number or Object is expected...int does not have any methods –MadProgrammer Oct 1 '13 at 6:09 add a comment| 5 Answers 5 active oldest votes up vote 9 down vote accepted id is of primitive type int and not an Object. You cannot call methods on a pr
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Int Cannot Be Dereferenced Java Meaning
about Stack Overflow the company Business Learn more about hiring developers or posting int cannot be dereferenced tostring ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack int cannot be dereferenced length Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up “Char cannot be dereferenced” error up vote 4 down vote favorite http://stackoverflow.com/questions/19109131/int-cannot-be-dereferenced-in-java I'm trying to use the char method isLetter(), which is supposed to return boolean value corresponding to whether the character is a letter. But when I call the method, I get an error stating that "char cannot be dereferenced." I don't know what it means to dereference a char or how to fix the error. the statement in question is: if (ch.isLetter()) { .... .... } Any help? What http://stackoverflow.com/questions/5527114/char-cannot-be-dereferenced-error does it mean to dereference a char and how do I avoid doing so? java char dereference share|improve this question edited Oct 19 '12 at 9:13 amesh 94221338 asked Apr 3 '11 at 2:05 user658168 3524713 1 Don't try to call methods on primitives. How about Character.isLetter(ch); –Hovercraft Full Of Eels Apr 3 '11 at 2:08 add a comment| 4 Answers 4 active oldest votes up vote 11 down vote The type char is a primitive -- not an object -- so it cannot be dereferenced Dereferencing is the process of accessing the value referred to by a reference. Since a char is already a value (not a reference), it can not be dereferenced. use Character class: if(Character.isLetter(c)) { share|improve this answer edited Apr 3 '11 at 2:18 answered Apr 3 '11 at 2:09 manji 36.3k36183 1 +1 - though it should also be noted that the . in Character.isLetter(c) denotes the use of a static method of Character. –Stephen C Apr 3 '11 at 3:34 add a comment| up vote 0 down vote I guess ch is a declared as char. Since char is a primitive data type and not and object, you can't call any methof from it. You sh
This Site Careers Other all forums Forum: Java in General What is meant by dereferencing? prabal saha Greenhorn Posts: 4 posted 15 years ago hi there, while compiling a program, i got this error: " byte cannot be dereferenced" please let me know what actually dereferencing is? prabal. Madhav https://coderanch.com/t/367369/java/java/meant-dereferencing Lakkapragada Ranch Hand Posts: 5040 posted 15 years ago Dereferensing means setting the reference to NULL. https://coderanch.com/t/563727/java/java/explain-null-pointer-dereference This way you are no longer referencing any obj. This is one way. Could you post your code..... regds. - satya Take a Minute, Donate an Hour, Change a Life http://www.ashanet.org/workanhour/2006/?r=Javaranch_ML&a=81 prabal saha Greenhorn Posts: 4 posted 15 years ago thanks Madhav, i got the point that was causing this eror.As for the code my approach was wrong. Frank Carver Sheriff Posts: 6920 cannot be posted 15 years ago 1 I don't agree with the explanation here. "dereferencing" actually refers to the process of getting or setting the value referred to by a reference. For example, If I say String s = "hello" then s is a reference to the actual characters. In this case I can dereference s to get the characters, but if I say, for example String s = null; then I can't dereference s, because it does not refer to any characters - cannot be dereferenced it is null! In the case of the initial question, I would imagine that the code was trying to call a method on a byte, and as byte is a primitive type which contains its own value, and not a reference to an Object, it could not be dereferenced. For example: byte b = 45; System.out.println(b.toString()); will not work (if you need to call a method, you should have used the object wrapper class Byte, instead), and neither will byte b; b[7] = 23; where the [] have inadvertently omitted from an array declaration. Read about me at frankcarver.me ~ Raspberry Alpha Omega ~ Frank's Punchbarrel Blog rehan hamid Greenhorn Posts: 16 posted 15 years ago In general, Reference is an address to some object/variable, While getting or setting value for that variable you need to de-reference that (means you need to get to that location where it is actually laying in the memory). Dereference is a common operation done by C++ programers. Hope this will clear Dereferencing. Michael Ernest High Plains Drifter Sheriff Posts: 7292 I like... posted 15 years ago Heya Frank - Thanks for your post. I don't use this particular term myself except by accident, partly because I've heard it used both ways with equal vigor and confidence. Judging only by the way I've most often seen it used, deferencing meaning "setting to null" seems the popular meaning for Java. Dereferencing meaning "get the value of" soun
This Site Careers Other all forums Forum: Java in General please explain null pointer dereference J. Kevin Robbins Bartender Posts: 1801 28 I like... posted 4 years ago I've been searching for an explanation of this message and can't find anything that clearly explains it. For instance, what's wrong with this code? public static String InputText(String id, String name, String value, String width, int maxLength, String className, boolean disabled, String tabIndex) { if (name == null || name.length() == 0 || value == null) { return ""; } StringBuilder xhtml = new StringBuilder(" 0) { xhtml.append(" id=\""); xhtml.append(id); xhtml.append("\""); } xhtml.append(" name=\""); xhtml.append(name); xhtml.append("\" value=\""); xhtml.append(value); xhtml.append("\""); if (width != null && width.length() > 0) { if (width.matches("\\d+")) { xhtml.append(" size=\""); xhtml.append(width); xhtml.append("\""); } else { xhtml.append(" style=\"width: "); xhtml.append(width); xhtml.append("\""); } } if (maxLength > 0) { xhtml.append(" maxlength=\""); xhtml.append(maxLength); xhtml.append("\""); } if (className != null && className.length() > 0) { xhtml.append(" class=\""); xhtml.append(className); xhtml.append("\""); } if (tabIndex != null && tabIndex.length() > 0) { xhtml.append(" tabindex=\""); xhtml.append(tabIndex); xhtml.append("\""); } if (disabled) { xhtml.append(" disabled"); } xhtml.append(" />"); return xhtml.toString(); } The FindBugs tool is telling me that line 5 contains a null pointer dereference to the id variable but I don't see the problem. It's simply a check to make sure the variable is not null. Why is that a problem? "The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." -- Ted Nelson Jesper de Jong Java Cowboy Saloon Keeper Posts: 15518 43 I like... posted 4 years ago 1 I don't see a problem in line 5. But I do see a problem in line 9: if (id != null || id.length() > 0) { When id == null, you will get a NullPointerException in this line, because then you'll be trying to call length() on a variable that's nu