Angular is a latest front-end framework of JavaScript, a development platform for building mobile and desktop web applications that makes you able to create reactive SPA (Single Page Applications). Angular framework is developed and main by Google. Angular framework is totally based on components forming a tree based on parent child component.

Angular comes with many features such as Component, Pipes, Directives, Forms, Dependency Injections etc.

SPA (Single Page Application)

Angular Tutorial: Getting Started With Angular 

1. What is Angular
2. Installation
3. Getting Started with Angular 
4. Angular Features
5. Differences between AngularJS and Angular
6. Angular Directives
7. Angular Pipes
8. Angular Databinding
9. Angular CLI
10. Forms
• Form Validation
• HTTP
• Router
• Module
• Styling
• Errors
• Configuration

package com.string.codebyakram;

import java.util.HashMap;

public class NonReapingCahr {
 public static void main(String[] args) {
  String string = "hello";
  System.out.println(findNonReapingCahr(string));
 }

 public static char findNonReapingCahr(String string) {

  HashMap< character > countChar = new HashMap<>();

  for (int i = 0; i < string.length(); i++) {
   int count = countChar.get(string.charAt(i)) == null ? 1 : countChar.get(string.charAt(i)) + 1;
   countChar.put(string.charAt(i), count);
  }

  for (int i = 0; i < string.length(); i++) {
   if (countChar.get(string.charAt(i)) == 1) {
    return string.charAt(i);
   }
  }
  return '\0';

 }
}

You can create multiple logs file by using same log4j properties file or you can send logs to multiple files by using same log4j file.

Add this below to your log4j properties file.

log4j.rootLogger=TRACE, stdout
log4j.appender.dataLogs=org.apache.log4j.FileAppender
log4j.appender.dataLogs.File=logs/logFile1.log
log4j.appender.dataLogs.layout=org.apache.log4j.PatternLayout
log4j.appender.dataLogs.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n
log4j.appender.reportsLog=org.apache.log4j.FileAppender
log4j.appender.reportsLog.File=logs/logFile2.log
log4j.appender.reportsLog.layout=org.apache.log4j.PatternLayout
log4j.appender.reportsLog.layout.ConversionPattern=%d [%24F:%t:%L] - %m%n

log4j.category.dataLogger=TRACE, dataLogs
log4j.additivity.debugLogger=false
log4j.category.reportsLogger=DEBUG, reportsLog
log4j.additivity.reportsLogger=false

Then configure the loggers in the code accordingly as shown below:

static final Logger debugLog = Logger.getLogger("dataLogger");
static final Logger resultLog = Logger.getLogger("reportsLogger");

package com.avaya.deletelogs;

import java.io.File;
import java.io.FilenameFilter;
import java.util.Arrays;
import java.util.List;

public class DeleteLogs {

 private String baseDir = "/opt/java/IVRLog";
 private int daysBack = 4;

 public void invokeProcess() {
  getFolders();
 }

 public void getFolders() {

  try {
   File file = new File(baseDir);
   String[] directories = file.list(new FilenameFilter() {

    public boolean accept(File current, String name) {
     return new File(current, name).isDirectory();
    }
   });
   deleteFiles(daysBack, baseDir, Arrays.asList(directories));
  } catch (Exception e) {
   System.out.println(e);
  }
 }

 public void deleteFiles(int daysBack, String dirWay, List< string> directories) {
  for (String dir : directories) {
   deleteFilesOlderThanNdays(daysBack, dir);
  }

 }

 public void deleteFilesOlderThanNdays(int daysBack, String dirWay) {

  File directory = new File(baseDir + "/" + dirWay);
  if (directory.exists()) {

   File[] listFiles = directory.listFiles();
   long purgeTime = System.currentTimeMillis() - (daysBack * 24 * 60 * 60 * 1000);
   for (File listFile : listFiles) {
    try {
     if (listFile.isFile()) {
      if (listFile.lastModified() < purgeTime) {
       if (!listFile.delete()) {
        System.err.println("Unable to delete file: " + listFile);
       }
      }
     } else {
      continue;
     }
    } catch (Exception e) {
     System.out.println(e);
    }
   }
  }
 }

}