Java heap space

[mickey]

Hello,
i write a program that creates many hashTable; it counts the frequency of each word in some document s(that it's very large). So there are many words... This is a part of code. Do you know how come overcome this problem (in general) ?

thanks

..............................
HashMap<String, Double> frequency = null;
  for (every document )  {
        frequency = new HashMap<String, Double>();
         //select a word and count
        frequecny.put( myWord , new Integer (count ) );
}
.................................................................

..............................
HashMap<String, Double> frequency = null;
  for (every document )  {
        frequency = new HashMap<String, Double>();
         //select a word and count
        frequecny.put( myWord , new Integer (count ) );
}
.................................................................

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Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
        at java.util.HashMap.resize(Unknown Source)
        at java.util.HashMap.addEntry(Unknown Source)
        at java.util.HashMap.put(Unknown Source)
        at MyClass.setting(MyClass.java:71)
        at filter.main(filter.java:19)

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
        at java.util.HashMap.resize(Unknown Source)
        at java.util.HashMap.addEntry(Unknown Source)
        at java.util.HashMap.put(Unknown Source)
        at MyClass.setting(MyClass.java:71)
        at filter.main(filter.java:19)

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[mickey]

I notice only now that the real problem seem to be here:

public String read(String filesDir, String file){
 
		 StringBuilder fileData = new StringBuilder(1000);		 
		 try {
			 BufferedReader  reader = new BufferedReader( new FileReader( new File(filesDir + "//" + file) ));
			 try {
				 char[] buf = new char[1024];
				 int numRead = 0;
				  while((numRead=reader.read(buf)) != -1){
					  fileData.append(buf, 0, numRead);
				  }
			 } finally { reader.close(); }
 
		 } catch (IOException e) {
			System.out.println("file not found");
			System.exit(-1);
 
		 }	
 
 
		return fileData.toString();

public String read(String filesDir, String file){
		
		 StringBuilder fileData = new StringBuilder(1000);		 
		 try {
			 BufferedReader  reader = new BufferedReader( new FileReader( new File(filesDir + "//" + file) ));
			 try {
				 char[] buf = new char[1024];
				 int numRead = 0;
				  while((numRead=reader.read(buf)) != -1){
					  fileData.append(buf, 0, numRead);
				  }
			 } finally { reader.close(); }
			 
		 } catch (IOException e) {
			System.out.println("file not found");
			System.exit(-1);
			 
		 }	
		 
		 
		return fileData.toString();

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on the "fileData.append(buf, 0, numRead);"
I've made a mistake: i have 2500 files to read.....
any suggestions?