Java - Random Helpful Tips

• Ternary Operator

This  will to reduce line number of  code . 

condition ? ifConditionTrueWhatShouldHappen : ifConditionFalseWhatShouldHappen

 This can  be use instead of ,Normal if  and  else .

•  Substring

•     public String substring(int startIndex) : 

   This method returns new String object containing the substring of the given string from specified     startIndex (inclusive). 

•     public String substring(int startIndex, int endIndex):  

  This method returns new String object containing the substring of the given string from specified     startIndex   to    endIndex (exclusive).

  Index starts  from 0  .Returns index where found, or -1 if not found 

ex :-  

String text = "Here there everywhere";

int a =text.indexOf("there");   // a is 5

int b =text.indexOf("er"); // b is 1 

int c =text.indexOf("eR"); // c is -1, "eR" is not found

•  For Checking Null

  if(foo != null && foo.bar()) {
     someStuff();
  }

  will use short-circuit evaluation, meaning it ends if the first condition of a logical AND is false.            
•  The && and || operators "short-circuit", meaning they don't evaluate the right hand side if it isn't        necessary. The & and | operators, when used as logical operators, always evaluate both sides.

• Variable Arguments (Varargs) in Java
   

• There can be only one variable argument in a method.
• Variable argument (varargs) must be the last argument.
• ex:-
  // Java program to demonstrate varargs

  class Test1

  {

      // A method that takes variable number of intger

      // arguments.

      static void fun(int ...a)

      {

          System.out.println("Number of arguments: " + a.length);

          // using for each loop to display contents of a

          for (int i: a)

              System.out.print(i + " ");

          System.out.println();

      }

      // Driver code

      public static void main(String args[])

      {

          // Calling the varargs method with different number

          // of parameters

          fun(100);         // one parameter

          fun(1, 2, 3, 4);  // four parameters

          fun();            // no parameter

      }

  }

How to Read Out Loud ,Pdf File etc and Listen to Them Later

If  we  able  to  convert    pdf  files   that  we  have  to read  ,to  audio  files ,It  will  be  great   help  to our   studies .


You  can   use   Adobe  Reader    to  read  out  loud , pdf   files  .But  I    there  is  no direct   way  to convert  those   files  to  MP3  files to  listen  later  .










You  can   use these   steps  in  this  web  page  to use    this  useful  method   Link - Simple Ways on How to Convert PDF to MP3 without any Fuss  .



There  is  other  softwares also ,  But   most  of  them  have  to  pay  to  pay  if  we  convert  them  to  MP3 file  , Watch  this video  .  So  i  think   earlier  way  will  be help most .






Hope   this will  help  to  your   studies . Try  it .