Try to find char u3000.

Test.java

import java.io.*;

public class Test{

	private static char SPACE='\u3000';

	public static void main(String[] args){

		if(args.length<1){
			System.exit(0);
		}

		File f=null;
		String ENC="SJIS";

		if(args.length>=1)
			f=new File(args[0]);
		if(args.length>=2)
			ENC=args[1];

		try{
			BufferedReader br= new BufferedReader(new InputStreamReader( new FileInputStream(f),ENC));

			String line=null;
			while( (line=br.readLine())!=null ){
				for(int i=0; i<line.length(); i++){
					if(SPACE==line.charAt(i)){
						int code=(int)(line.charAt(i));
						System.out.println("Found ideographics space: "+Integer.toHexString(code) );
					}
					else{
						System.out.println(line.charAt(i));
					}
				}
			}
			br.close();
		}
		catch(Exception ex){
			ex.printStackTrace();
		}
	}
}