File Search

Approaches
A simple technique that could well be considerably faster than indexOf() is to use a Scanner, with the method findWithinHorizon(). If you use a constructor that takes a File object, Scanner will internally make a FileChannel to read the file. And for pattern matching it will end up using a Boyer-Moore algorithm for efficient string searching.

I think this program still loads the whole file into memory. I am facing OOM exceptions when trying with large files.

Another link

public static void searchFile() {
    	  //File file = new File("C:\\Data\\wwwData\\_backup\\full_04.2022\\auth.log");
    	  File file = new File("C:\\Data\\wwwData\\_backup\\full_04.2022\\lib\\mysql_bak\\ibdata1");
    	  
    	  System.out.println("Start");
	      try {
	          int count = 0;
	          FileReader fileIn = new FileReader(file);
	          BufferedReader reader = new BufferedReader(fileIn);
	          String line;
	          while((line = reader.readLine()) != null) {
	              if((line.contains("pydct"))) {	                  
	                  System.out.println("Line number " + count);
	              }
	              count++;
	          }
	          reader.close();
	      }catch (IOException e){
	          System.out.println(e);
	      }  
	      System.out.println("Finish");
      }
      
      public static void searchFile2() {
    	    int tot = 0;
    	    System.out.println("Start");
    	    Pattern pattern = Pattern.compile("BARCELONA");
    	    
    	    try {
    	    	Scanner scan = new Scanner(new File("C:\\Data\\wwwData\\_backup\\full_04.2022\\lib\\mysql_bak\\ibdata1"));
    	        while (scan.findWithinHorizon(pattern, 0) != null)
    	            tot++;
	  	      }catch (FileNotFoundException e){
		          System.out.println(e);
		      }    
    	    System.out.println("Results found: " + tot);
    	}

Crop String

public static String cropString(String s, int k) {
    	 if(k < 1) return ""; 
    	 if(k >= s.length()) return s;
    	 String part = s.substring(0, k+1);
    	 return part.substring(0, part.lastIndexOf(" "));      
      }
      
      public static String cropString1(String s, int k) {
    	  if(k < 1) return ""; 
     	 if(k >= s.length()) return s;
     	 while(s.charAt(k) != ' ')
     		 k--;
     	 return s.substring(0, k);      
       }