convert json to single line

jsonSingleLine.java

package jsonFormatter;

import java.io.*;
import java.nio.file.FileVisitResult;
import java.nio.file.FileVisitor;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.SimpleFileVisitor;
import java.nio.file.attribute.BasicFileAttributes;
import java.io.IOException;

public final class importer {
	  
	  public static void main(String... aArgs) throws IOException{
		
	    String ROOT = "/Users/davidfauth/bills/109";
	    FileVisitor<Path> fileProcessor = new ProcessFile();
	    Files.walkFileTree(Paths.get(ROOT), fileProcessor);
	  }

	  private static final class ProcessFile extends SimpleFileVisitor<Path> {
	    @Override public FileVisitResult visitFile(
	      Path aFile, BasicFileAttributes aAttrs
	    ) throws IOException {
	    	FileWriter fileWriter = null;
	    	String absolutePath = "";
	    	String filePath="";
	    	String outFilePath = "";
	    	File f = new File(aFile.toString());
	    	System.out.println(f.getName());
	    	absolutePath = f.getAbsolutePath();
	    	filePath = absolutePath.substring(0,absolutePath.lastIndexOf(File.separator));
//	    	System.out.println("file path is: " + filePath);
//	    	System.out.println("new file path is: " + filePath.substring(17));
	    	
	    	outFilePath = "/Users/davidfauth/MortarData/" + filePath.substring(18).replace("/", "_");;
	    	System.out.println("new file is " + outFilePath);
	    	if (f.getName().toString().equals("data.json")){
	    		System.out.println("Processing file:" + aFile);
	    		
	    		BufferedReader br = new BufferedReader(new FileReader(aFile.toString()));
	    		try {
	    			StringBuilder sb = new StringBuilder();
	    			String line = br.readLine();

	    			while (line != null) {
	    				sb.append(line);
	    				sb.append(" ");
	    				line = br.readLine();
	    			}
	    			File newTextFile = new File(outFilePath+"_data1.json");
	                fileWriter = new FileWriter(newTextFile);
	                fileWriter.write(sb.toString());
	                fileWriter.close();
	    		} finally {
	    				br.close();
	    		}	
	    	}
	      return FileVisitResult.CONTINUE;
	    }
	    
	    @Override  public FileVisitResult preVisitDirectory(
	      Path aDir, BasicFileAttributes aAttrs
	    ) throws IOException {
//	      System.out.println("Processing directory:" + aDir);
	      return FileVisitResult.CONTINUE;
	    }
	  }
	}