Tech Trek: A Software Engineer's Guide to Code and Beyond

The HashMap class uses a hash table to implement the Map interface. This allows the execution time of basic operations, such as get() and put() , to remain constant even for large sets. The following constructors are defined:   HashMap( ) HashMap(Map m ) HashMap(int capacity ) HashMap(int capacity , float fillRatio )   Hash map does not guarantee the order of its elements. Therefore, the order in which elements are added to a hash map is not necessarily the order in which they are read. Here is the code:   import java.util.HashMap; import java.util.Map; /**  *  * This Java HashMap example describes the basic operations performed on the HashMap  * @author abdul  *  */ public class HashMapExample {     public static void main(String args[]){                 // constructs a new empty HashMap with default initial capacity   ...

JDK 1.6 provides few new methods  getTotalSpace() , getFreeSpace() , bundled with java.io.File. These methods provides essential information regarding disk space. getFreeSpace() method -   Returns the number of unallocated bytes in the partition named by this abstract path name. getTotalSpace() method - Returns the size of the partition named by this abstract pathname. Here is the code:  import java.io.File; /**  * Program that returns the number of unallocated bytes , total space in the partition.  *  * @author abdul  *  */ public class DiskDetail {     public static void main(String[] args) {         File file = new File("C:");         long totalSpace = file.getTotalSpace(); // total disk space in bytes.         long freeSpace = file.getFreeSpace(); // unallocated / free disk space   ...

I was getting a Exception like, javax.xml.bind.JAXBException: "doesnt contain ObjectFactory.class or jaxb.index" while trying to create a JAXBContext using JAXBContext.newInstance(String contextPath). It took me a while to figure out what went wrong. So now that I've got things working correctly, I thought I'd post this example and solution to hopefully save you some time. When we create a marshaller, we first need to create a JAXBContext via its newInstance() factory method. You can create a context for a specific JAXB class  or you can create a context for a list of packages. There are two ways to resolve this issue :    - By creating ObjectFactory   - By adding jaxb.index file jaxb.index : The jaxb.index file is a text file contains a listing of the classes on the containing package that have JAXB annotations. Note : The name of the clases is their simple name not their classified name.   Rather than creating a ObjectFactory, I guess adding ...