In android coding i have two different arraylist. i have matched both arraylist elements. But my problem is that when my matched data found  in loop, if statement not running. this is my code  for (int i = 0; i &lt; mname.size(); i++)  {     if(i&lt;jsonArray.length())     {      JSONObject jo = jsonArray.getJSONObject(i);      String paid = jo.getString("name");      instname.add(paid);      }      else      {      instname.add("0");      }      System.out.println(instname.get(i)+ "  " + i );      for(int j=0;j&lt;mname.size();j++)      {          System.out.println("instname "+i + "  " + "mname  "+j);          if(instname.get(i) == mname.get(j))          {              System.out.println("instnam=" + instname.get(i));              System.out.println("mem="+ mname.get(j));              pay = instname.get(i);              break;          }      } }   Here in code mname and instname is arraylist. mname has 2 names, 'name1' and 'name2' and instname hase 1 name, 'name2'. In my logcat result like      name2  0     instname 0  mname  0     instname 0  mname  1     0  1     instname 1  mname  0     instname 1  mname  1   instname 0 and mname 1is true matched data contains both name2, but my if condition not run. it results pay = null
I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?
Why is a nonstop flight sometimes more expensive than multiple connections? I'm trying out  with gnuplot to generate the data.  This works by having pgfplots write some stuff to an external file, run gnuplot on the file, and then use the generated data to plot the graph.  The problem I'm having is that I get different behaviour under xelatex as pdflatex or lualatex.  In xelatex, the data file is littered with ^^I whereas in the other two formats these are tabs.  It appears that the code ^^I is getting stored as a macro which then gets written out to the file, so possibly there's something funny going on with the ^^I syntax: xelatex is reading it literally.  Indeed, when I do \show\pgfplots@TAB (the macro in question) then for pdflatex and lualatex then I get a literal tab whereas for xelatex I get ^^I.  So how do I get a tab in xelatex?  And why isn't \gdef\pgfplots@TAB{^^I} working?  (The previous line in the code, by the way, is \catcode`\^^I=12 - I don't know if that has anything to do with it.) When transfering data using TLS the browser and server agree the cipher suite to be used - so for example this could be chosen as AES-128 and is (probably) outside of my control. If I separately encrypt a file using AES-256 and then Alice downloads this via her browser (using AES 128) have I still effectively got AES-256 security?  My reasoning goes like this: even if the AES-128 encryption on the TLS link was broken by Eve then all she would get is the AES-256 encrypted file and she would then have to break that encryption to see the plaintext.  Of course the AES-256 key is sent to Alice over a separate channel. how to remove frost free outdoor faucet drain valve assembly I've tried unscrewing the part outlined in red below. No dice. Do I just need to remove the whole rod (above the red outline) and replace it?) If so, can anyone point me to instructions for them.  I can't see in there. Worried that I'll pull it out and not be able to put it back in.  (The deeper I go in the plumbing the more things I find that there is no modern fitting-part :)  My new assembly  replaces the parts outlined in red. the new assembly has a female thread. I am HOPING that the thicker part of the pipe (just above the black "collar" stopper)  is screwed onto the pipe above.  However, I cannot unscrew it. There is nothing to get a hold of. It's perfectly round. I've tried dw40, and let it sit for 20 minutes. No love.  I'll try wacking it with a board in the direction along which it moves in when it screws (perpendicular to the threads per [this answer][2]) How to handle dynamic changing ID's In XPath? How to Handle Dynamic Changing IDs In XPath? for example :   //div[@id='post-body-3647323225296998740']/div[1]/form[1]/input[1]   In this xpath id "3647323225296998740" is changing every time when reloading the page.   Is there any way to handle this type of situation in Selenium? This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading Macbook Pro 13" 2015 with OS X Yosemite on board. I've been trying to install OS X El Capitan, but always get the following message:  "This copy of the Install OS X El Capitan application can't be verified. It may have been corrupted or tampered with during downloading."  By the way this is not a date time issue, date is correct on my computer.    How can I fix this? Who knows the solution, please help. Pointwise convergent and total variation Command to perform a recursive chmod to make all .sh files within a directory executable? I'm using this code to get standard output from an external program:  &gt;&gt;&gt; from subprocess import * &gt;&gt;&gt; command_stdout = Popen(['ls', '-l'], stdout=PIPE).communicate()[0]   The communicate() method returns an array of bytes:  &gt;&gt;&gt; command_stdout b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2\n'   However, I'd like to work with the output as a normal Python string. So that I could print it like this:  &gt;&gt;&gt; print(command_stdout) -rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1 -rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2   I thought that's what the  method is for, but when I tried it, I got the same byte array again:  &gt;&gt;&gt; binascii.b2a_qp(command_stdout) b'total 0\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file1\n-rw-rw-r-- 1 thomas thomas 0 Mar  3 07:03 file2\n'   How do I convert the bytes value back to string? I mean, using the "batteries" instead of doing it manually. And I'd like it to be OK with Python&nbsp;3. Let $E|F$ be an algebraic field extension and a ring $K$ such that $F\subseteq K\subseteq E$. It is true that $K$ is a field? Calculate the sum of inverse values of ${n\choose 0}, {n\choose 1}, ... {n\choose n}$ Calculate $$A={1\over {n\choose 0}}+ {1\over {n\choose 1}}+ ...+{1\over  {n\choose n}}$$  and  $$B={1\over {n\choose 0}}- {1\over {n\choose 1}}+ ...+{(-1)^n\over  {n\choose n}}$$     My idea for $A$ is some probabilistic reasoning. Color the sets $$\{\}, \{1\}, \{1,2\}, \{1,2,3\},...\{1,2,...,n\}$$ and ask our self what is the probability that I choose colored set among all sets. Clearly this is exactly ${n+1\over 2^n}$ and on the other side it is $A$:  probability that I take empty set is ${1\over {n\choose 0}}$,   probability that I take colored set with 1 element is ${1\over {n\choose 1}}$  probability that I take colored set with 2 elements is ${1\over {n\choose 2}}$  and so on ...   So $A ={n+1\over 2^n}$. But I have no idea how to attack $B$. I ran into an interesting behavior recently.  It seems that if I override .equals() to take a parameter other than Object, it doesn't get called.  Can anyone explain to me why this is happening?  It seems to violate my understanding of polymorphism in OOP, but maybe I'm missing something.  Here's much simpler code that shows what I'm seeing:  public class MyClass {   private int x;   public MyClass(int n) { x = n; }   public boolean equals(Object o) { return false; }   public boolean equals(MyClass mc) { return x == mc.x; }   public static void main(String[] args) {     List&lt;MyClass&gt; list = new ArrayList&lt;MyClass&gt;();     list.add(new MyClass(3));     System.out.println("Contains 3? " + list.contains(new MyClass(3)));   } }   When this is run, it prints "Contains 3? false".  It looks like the equals(Object) function is called, even though there is another that would work.  By contrast, if I write equals like this the code works as expected:  public boolean equals(Object o) {   if(!(o instanceof MyClass))     return false;   MyClass mc = (MyClass)o;   return x == mc.x; }   Why isn't it figuring out which version of the function to call based on the type of the parameter? Multiplication in Permutation Groups Written in Cyclic Notation OS X Yosemite brought support for recording iPhone/iPad screen natively without having to using AirPlay applications like AirServer or Reflector.   How do I record the iPhone screen on macOS ? External hard disk detection issue what exactly happened:  I have a Seagate 1 TB external hard disk.It was working fine till now.The problem started when I plugged it in my android phone and then back in my pc then simply it does not showup anywhere and :  It does not appear in file explorer   It does not appear in disk management   It is not listed in Diskpart command   It only appears in Device Manager under disk drives   It does not appear in BIOS  only makes sound when plugged and unplugged.  disk spins and light is also showing.   . What I already tried:   updated usb drivers.  used new cable also.  plugged in another pc  usb mass storage is also enabled in BIOS  no issue in any usb port  Anything else i can do? I was thinking about something the other day (that is probably stupid), and thought this would be a good place to talk about it.  If someone wanted to draw its family tree over the last 1000 years, he'd write a binary tree with a depth of about 40 (counting 25 years on average between each generations). This tree would have 240 leaves, or about 1012 ancestors on the deeper level. That is obviously much more than the total world population and a stupid figure when you think about it.  The only explanation that I can think of is that a real genealogy tree must have "linked" branches at several levels that change the actual number of ancestors. Anyway, for an average person, how many ancestors would that make? Could one assume that all or nearly all of the persons that lived in its country or world region a 1000 years ago would be part of its ancestors? What's a recommended alternative to Quickbooks pro? I've just installed Ubuntu to replace Windows. I can't seem to find a good alternative to  to run on Ubuntu. Any help would be appreciated. Wrong kernel version returned by uname Ubuntu 16.04.1 LT uname -a returns:    Linux decebal-mobile 4.2.0-35-generic #40-Ubuntu SMP Tue Mar 15 22:15:45 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux   but E: Package 'linux-headers-4.2.0-35-generic' has no installation candidate  and my machine says linux headers version is at linux-headers-4.4.0-21-generic.   I have seen a similar problem described in a .  How can I update that? Prepend phone numbers with a calling card dial in number Include chapters in List of Figures with titletoc?