Map (Hashmap) to Array

Hello Java Friends,
Please, I have a map (Mappings = new HashMap<String, Integer>) which contains both String and Integer elements. I wanted to store the string elements of the Map in a String Array and Integer elements in Integer Array but end up with error messages. How can I implement it?
See part of my code below:
public class Tryit{
private Map<String, Integer> Mappings;
String[]StringElem;
int [] IntegerElem;
public Tryit(){
Mappings = new HashMap<String, Integer>()
StringElem = new String [100];
IntegerElem = new int [100];
for (String index : Mappings.KeySet()){
StringElem = index;
for (int i : Mappings.values(){
IntegerElem = i;
}

Hello friends,
The idea you gave me worked but still I am having a small problem: I have two classes, class A and B. In Class A, I implemented a set and get method which I will use in Class B to retrieve the keys and Values. But when I call the get method in Class B, I always get null. The arrays in both classes are all declared globally.
Get and Set Method in Class A :
public void setKeyValues() {
          int i = 0;
          for(Map.Entry<String, Integer> e: map.entrySet()) {
               ElementName= e.getKey();
          i++;
public String []getKeyValues(){
     return ElementName;
Call the Get Method in Class B
import package X.A
public class B{
private String [] names;
public B(){
A bix = new A();
int length = bix.getKeyValues().length;
names = new String[length];
System.out.printf ("%d", gettingKeys(bix.getKeyValues());
public String[] gettingKeys(String []naming) {
          names = new int[bix.getKeyValues().length];
          int size = naming.length;
          for (int p = 0; p < size; p++) {
               names[p]=naming[p];
               p++;
          return names;
     }Please where is the problem ?? I am unable to read and print the map values and keys from another friend class.
Jona_T

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It is correct that b is referring to the same object that the map's key is pointing to, but why does the following
print null , instead of "somevalue"?
at these lines in the code above.
b.name = "sparrow";
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A hashtable gets its good efficiency by not having to look through all values to find the pair. It can jump directly to the correct bucket, which takes constant time instead of being dependent on the number of items in the collection.
endasil wrote:
You should never, ever change an object being used as a key in a map.I guess this is a best practice, I just wanted to try changing the key object to test a few things for SCJP, which does not test on coding best practices but tests on how the code behaves.Yep, and what you should take away is that this is WHY it's bad to change the key :).

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Hi Ronni
This forum is not the right place where you can find your answer easily. To catch more answers you can try posting your question to one of the following forums:
1. <a href="https://www.sdn.sap.com/sdn/collaboration.sdn?node=linkFnode1-1&contenttype=url&content=https%3A%2F%2Fforums.sdn.sap.com%2Fforum.jspa%3FforumID%3D41">EP Content Development Forum</a>
2. <a href="https://www.sdn.sap.com/sdn/collaboration.sdn?node=linkFnode2-4&contenttype=url&content=https%3A%2F%2Fforums.sdn.sap.com%2Fforum.jspa%3FforumID%3D59">Java Programming Forum</a>
*--Serdar
Moved the post to Java Programming.
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Message was edited by: Mark Finnern

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I give an sample below.
source:
<Items xmlns="http://www.example.org/sample">
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<ns1:AttributesCollection>
<ns1:Attributes>
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<ns1:Attributes>
<ns1:fieldname>TimeStamp</ns1:fieldname>
</ns1:Attributes>
<ns1:Attributes>
<ns1:fieldname>ID</ns1:fieldname>
</ns1:Attributes>
<ns1:Attributes>
<ns1:fieldname>Type</ns1:fieldname>
</ns1:Attributes>
<ns1:Attributes>
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<xs:complexType name="AttributesCollection">
<xs:sequence>
<xs:element name="Attributes" type="Attributes" minOccurs="0" maxOccurs="unbounded"/>
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<xs:complexType name="Attributes">
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Edited by: user1065212 on 17-Jan-2010 22:50
Edited by: user1065212 on 17-Jan-2010 22:53
Edited by: user1065212 on 17-Jan-2010 22:59

can you paste source xsd and the correct xml output, the current one isn't really valid
<ID>2574</TotalNumOfItems>

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I was given an object model generated by an apache product, Axis. The generated java files use the Java Array in the following fashion:
Class Zoo {
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// â¦ public get/set methods cut
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// â¦ public get/set methods cut
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My program reads the data from the external file called: "long.txt" which consists of a million records...
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^
HashMapTestnew.java:38: cannot resolve symbol
symbol : class MyData
location: class MyData.HashMapTestnew
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^
HashMapTestnew.java:55: cannot resolve symbol
symbol : class MyData
location: class MyData.HashMapTestnew
MyData md;
^
HashMapTestnew.java:66: cannot resolve symbol
symbol : class MyData
location: class MyData.HashMapTestnew
md = (MyData) me.getValue();
^
4 errors
Tool completed with exit code 1
import java.util.*;
import java.io.*;
public class HashMapTestnew
public static HashMap getMapList()
String MyData;
Int sKey;
String strLine;
HashMap hm = new HashMap();
try
BufferedReader fBR = new BufferedReader( new FileReader("long.txt") );
while ( fBR.ready() )
strLine = fBR.readLine();
if (strLine != null)
StringTokenizer st = new StringTokenizer(strLine, "\t");
String sKey = st.nextToken();
String sVal = st.nextToken();
MyData md = new MyData( sKey, Integer.parseInt(sVal) );
hm.put(sKey, md);
fBR.close();
catch (IOException ioe)
System.out.println("I/O Trouble ...");
return hm;
public static void showMapList(HashMap hashMap, int n)
String strVal;
String strNdx;
MyData md;
System.out.println("\nHashMap List (first 10 records):");
Map.Entry me;
Set shm = hashMap.entrySet();
Iterator j = shm.iterator();
int i = 0;
while (j.hasNext() && (i++)< n)
me = (Map.Entry) j.next();
strVal = (String) me.getKey();
md = (MyData) me.getValue();
System.out.println(i + ": " + md.getVal() + "\t" + md.getNdx() );
public static String[] getKeys(HashMap hashMap)
String[] key = new String[hashMap.size()];
Map.Entry me;
Set shm = hashMap.entrySet();
Iterator j = shm.iterator();
int i = 0;
while (j.hasNext())
me = (Map.Entry) j.next();
key[i] = (String) me.getKey();
i++;
return key;
public static void searchMapList(HashMap hashMap, String[] key)
int i,n=0;
System.out.println("Search Started:");
long tim1 = System.currentTimeMillis();
for (i=0; i<key.length; i++)
if (hashMap.containsKey(key))
n++;
long tim2 = System.currentTimeMillis();
System.out.println("Search Ended After " + (tim2-tim1) + " miliseconds.");
System.out.println("Searched for " + key.length + " keys.");
System.out.println("Found " + n + " keys.");
public static void main(String[] arg)
HashMap hashMap = getMapList(); // Create the hash map list
showMapList(hashMap, 10); // Display part of the hash map list
String[] searchKey = getKeys(hashMap); // an array of all search keys
searchMapList(hashMap, searchKey); // Search for all existing keys in the list
Can anybody help me with this?
I'm new to Java... What does the error message: "cannot resolve symbol
symbol : class MyData" mean???
P.S. When I compiled the file "MyData.java", it compiles without any error...
Thanks,
Lilian

I moved the 3 files ("MyData.java", "long txt" and "HashMapTest.java") to a directory called "MyData" as well as added the code: "package MyData;"
before the codes:
import java.util.*;
import java.io.*;
just to see if it would make any difference but I still got the following error messages:
C:\WINDOWS\DESKTOP\MyData\HashMapTest.java:38: cannot resolve symbol
symbol : class MyData
location: class MyData.HashMapTest
MyData md = new MyData( sKey, Integer.parseInt(sVal) );
^
C:\WINDOWS\DESKTOP\MyData\HashMapTest.java:38: cannot resolve symbol
symbol : class MyData
location: class MyData.HashMapTest
MyData md = new MyData( sKey, Integer.parseInt(sVal) );
^
C:\WINDOWS\DESKTOP\MyData\HashMapTest.java:55: cannot resolve symbol
symbol : class MyData
location: class MyData.HashMapTest
MyData md;
^
C:\WINDOWS\DESKTOP\MyData\HashMapTest.java:66: cannot resolve symbol
symbol : class MyData
location: class MyData.HashMapTest
md = (MyData) me.getValue();
^
4 errors
Tool completed with exit code 1
By the way, I'm compiling the java program using a Textpad editor and selecting Tools -->> Compile Java...
Let me know if you have any questions...
Thanks,
Lilian
location: class MyData.HashMapTestnewThis says that you have declared your HashMapTestnew
class to be in package MyData.
I have the files: "long.txt", "HashMapTestnew.java"and "MyData.java" in the same directory called:
"tmp"...
If you want HashMapTestnew to be in package MyData,
then it should have been in a directory called MyData.
But having a class with the same name as a package is
very confusing, so I don't think you should do that.
In fact, since you are new to Java I don't think you
u should use packages at all until you can compile
non-packaged classes correctly.
I'm surprised I don't see the line "package MyData" at
the top of the code you posted. But then I'm not
surprised, because since your class isn't in the right
directory for that package, you should have got
different error messages. What exactly did you type
at the command line to compile the class?

How to loop through an associative array

Guys,
How to loop through an associative array. where the key is string but the value is an object
-Thanks

It depends if you are using a Java HashMap or a BPM Associative array. You'd use the "keySet" if for the former and the "keys" if it's the latter.
I know you want an object for the array, but Any[String] is used here just so you can see something coming back in the display statements shown below. Remove the input and display statements - they're just in there so you can see something working.
Here's how to go through a Hashmap's array using a loop:
map as Java.Util.HashMap
map.put(1, "One")
map.put(2, "Two")
map.put(3, "Three")
map.put(4, "Four")
map.put(5, "Five")
display map.keySet
for each item in keySet(map) do
     display item
     display get(map, arg1 : item)
endHere's how to go through an associative array using a loop:
hashMap as Any[String]
hashMap = ["One": 1,"Two":2]
for each item in hashMap.keys do
     display item
     display "Item in the array is: " + hashMap[item]
endDan

Array Of Primitive Type (kodo3.4)

Hello,
I want to map an array of primitive type (double[] or double[][] or...) to
a blob, so I specified the mapping this way:
<extension vendor-name="kodo" key="jdbc-field-map-name" value="blob">
<extension vendor-name="kodo" key="column" value="DATA"/>
</extension>
As I use MySQL and not to have an exception, I have added:
kodo.jdbc.DBDictionary: DriverDeserializesBlobs=false
But when I tried to refresh using kodo.jdbc.meta.MappingTool, I get:
[refresh] Exception in thread "main" kodo.util.FatalInternalException:
Cannot map "fr.ifp.reservoir.model.business.geostat.Lithotype.facies".
Check the class and make sure you are using only supported types.
[refresh] at
kodo.jdbc.meta.DynamicMappingProvider.createFieldMapping(DynamicMappingProvider.java:336)
[refresh] at
kodo.jdbc.meta.DynamicMappingProvider.getFieldMapping(DynamicMappingProvider.java:118)
[refresh] at
kodo.jdbc.meta.MappingRepository.getFieldMapping(MappingRepository.java:470)
[refresh] at
kodo.jdbc.meta.AbstractClassMapping.getFieldMapping(AbstractClassMapping.java:993)
[refresh] at
kodo.jdbc.meta.AbstractClassMapping.getFieldMapping(AbstractClassMapping.java:973)
[refresh] at
kodo.jdbc.meta.AbstractClassMapping.getMappings(AbstractClassMapping.java:939)
[refresh] at
kodo.jdbc.meta.AbstractClassMapping.getDeclaredFieldMappings(AbstractClassMapping.java:659)
[refresh] at
kodo.jdbc.meta.AbstractClassMapping.resolve(AbstractClassMapping.java:801)
[refresh] at
kodo.jdbc.meta.BaseClassMapping.resolve(BaseClassMapping.java:341)
[refresh] at
kodo.jdbc.meta.MappingRepository.resolve(MappingRepository.java:431)
[refresh] at
kodo.jdbc.meta.MappingRepository.getMapping(MappingRepository.java:349)
[refresh] at
kodo.jdbc.meta.MappingRepository.getMapping(MappingRepository.java:177)
[refresh] at kodo.jdbc.meta.MappingTool.refresh(MappingTool.java:591)
[refresh] at kodo.jdbc.meta.MappingTool.run(MappingTool.java:941)
[refresh] at kodo.jdbc.meta.MappingTool.run(MappingTool.java:879)
[refresh] at kodo.jdbc.meta.MappingTool.main(MappingTool.java:802)
Thanks for your help.
nicolas

Hi,
No more succes with persistence-modifier="persistent"...
My class:
public class ArrayWrapper {
private String name;
private double[] array;
public ArrayWrapper(String name, double[] array) {
this.name = name;
this.array = array;
public double[] getValues() {
return array;
public String getName() {
return name;
My metadata file:
<jdo>
<package name="model">
<class name="ArrayWrapper">
<field name="array" persistence-modifier="persistent">
<extension vendor-name="kodo" key="jdbc-field-map-name" value="blob">
<extension vendor-name="kodo" key="column" value="DATA"/>
</extension>
</field>
</class>
</package>
</jdo>
My StackTrace:
refresh-mapping:
[java] Exception in thread "main" kodo.util.FatalInternalException:
Cannot map "model.ArrayWrapper.array". Check the class and make sure you
are using only supported types.
[java] at
kodo.jdbc.meta.DynamicMappingProvider.createFieldMapping(DynamicMappingProvider.java:336)
[java] at
kodo.jdbc.meta.DynamicMappingProvider.getFieldMapping(DynamicMappingProvider.java:118)
[java] at
kodo.jdbc.meta.MappingRepository.getFieldMapping(MappingRepository.java:470)
[java] at
kodo.jdbc.meta.AbstractClassMapping.getFieldMapping(AbstractClassMapping.java:993)
[java] at
kodo.jdbc.meta.AbstractClassMapping.getFieldMapping(AbstractClassMapping.java:973)
[java] at
kodo.jdbc.meta.AbstractClassMapping.getMappings(AbstractClassMapping.java:939)
[java] at
kodo.jdbc.meta.AbstractClassMapping.getDeclaredFieldMappings(AbstractClassMapping.java:659)
[java] at
kodo.jdbc.meta.AbstractClassMapping.resolve(AbstractClassMapping.java:801)
[java] at
kodo.jdbc.meta.BaseClassMapping.resolve(BaseClassMapping.java:341)
[java] at
kodo.jdbc.meta.MappingRepository.resolve(MappingRepository.java:431)
[java] at
kodo.jdbc.meta.MappingRepository.getMapping(MappingRepository.java:349)
[java] at
kodo.jdbc.meta.MappingRepository.getMapping(MappingRepository.java:177)
[java] at kodo.jdbc.meta.MappingTool.refresh(MappingTool.java:591)
[java] at kodo.jdbc.meta.MappingTool.run(MappingTool.java:941)
[java] at kodo.jdbc.meta.MappingTool.run(MappingTool.java:879)
[java] at kodo.jdbc.meta.MappingTool.main(MappingTool.java:802)

Converting bytes to character array problem

I am trying to convert a byte array into a character array, however no matter which Character Set i choose i am always getting the '?' character for some of the bytes which means that it was unable to convert the byte to a character.
What i want is very simple. i.e. map the byte array to its Extended ASCII format which actually is no change in the bit represtation of the actual byte. But i cannot seem to do this in java.
Does anyone have any idea how to get around this problem?

Thanks for responding.
I have however arrived at a solution. A little un-elegant but it seems to do the job.
I am converting each byte into char manually by this algorithm:
          for (int i=0;i<compressedDataLength;i++)
               if (((int) output)<0)
                    k=(127-((int) output[i]));
                    outputChr[i]=((char) k);
               else
                    k=((int) output[i]);
                    outputChr[i]=((char) k);
               System.out.println(k);
where output is the byte array and outputChr is the character array

Map (Hashmap) to Array

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