Object « HashTable « Java Collection Q&A

1. How big is an empty Hashtable object    stackoverflow.com

What is the size (in bytes) of the Hashtable object in J2ME? I mean what is the overhead for using a Hashtable?

2. how to find and return objects in java hashset    stackoverflow.com

According to the HashSet javadoc, HashSet.contains only returns a boolean. How can I "find" an object in a hashSet and modify it (it's not a primitive data type)? I see that HashTable ...

3. Java graph library with List of objects instead of hash tables    stackoverflow.com

I've tried JGraphT It looks very promising but my problem is that my objects are changing and I want the Graph to map objects as a List not through hash table. ...

4. If key in hashtable is a class object, how does containsKey work?    stackoverflow.com

When we put a class Object (that has say three data members) in a hashtable, how can I prevent putting another entry into the hash table whose key has the same ...

5. Java object comparison and Hashtable with Object keys    stackoverflow.com

Suppose I have an MyObject class, and it's stored in 2 different ArrayList. If get the same object from the 2 ArrayList, how would I compare them to check if they're ...

6. Accessing HashTable within an object    coderanch.com

7. How to get date/time an object is added to a Hashtable    coderanch.com

Er, no, that's not going to help is it?! In your code, you store only a Date. The original poster wants to know what time and date some entry was added. That entry isn't going to be a Date. The Hashtable and HashMap classes don't provide such a facility, because it would eat up lots of memory and CPU, storing the ...

8. How to write a class use Hashtable to add, update, delete an Object....?    coderanch.com

Hi all I have an User.java class, include the fields: String name; int age; public class User { private String name; private String age; /* * Getter and Setter. */ public String getName() { return name; } public void setName(String name) { this.name = name; } public String getAge() { return age; } public void setAge(String age) { this.age = age; ...

9. I need to retrieve an Object[] of all keys in java.util.Hashtable    forums.oracle.com

10. How to use Hashtable in Rules Engine. And objects within objects in rules    forums.oracle.com

This is something to do with the JBoss Rules Engine. I have an object called 'Employee' containing variables name(string), age(int), ***(string), an object Skill and other fields not relevant. Now the Skill object contains name and desc as variables. And now i have another seperate object called Test containing two hashtable: inputHT and outputHT. i have appropriate data in each of ...

11. How to handle objects which were digged out of a hashtable??    forums.oracle.com

Since I'm forced to use Java 1.4, the cast from Object to car was the solution for me... Also, you should probably use the Map and HashMap (without the generics stuff) instead of Hashtable. If you really need the synchronization (that Hashtable has), lookup Collections.synchronizedMap. Well as far as i think Hastable is not all of being sychronized but it does ...

12. Changing values in an object stored in a Hashtable    forums.oracle.com

If i retrieve an object stored in a Hashtable and change some of its attributes - do I need to put the updated object back in the Hashtable? Or will the object be updated inside the table? It depends. You don't have to add the object back UNLESS any of the attributes you changed are used in the hashCode and equals ...

13. Trying to return a Hashtable object    forums.oracle.com

were your method to return a Map rather than a HashMapyou could transparently return either a HashMap or a HashTable - or anything else that implements the Map interface - without changing any of the code that actually calls this method. you will still, obviously, need to instantiate one inside the method hence the mantra "code to an abstraction, not ...