What am I doing wrong in here:  public void processFinish(String[] result) {     System.out.println(result[0]);     System.out.println(result[1]);     System.out.println(result[2]);      if(result[0] == "true")         comments.setText("Success");     else if (result[1] == "true" &amp;&amp; result[2] == "false")         comments.setText("Username is already used");     else         comments.setText("Phone number is already used"); }   The output is: true false false  Yet, it always executes the else clause !!!
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?
Font characters displayed as squares in Ubuntu 18.04 Recently, on my Ubuntu 18.04 I have noticed that at least on gnome-calculator and chromium browser the fonts are displayed as squares. I have followed instructions  and , the calculator is fixed, but the problem on chromium still exists when I open a dialog to search for a file.  Not sure if this happens on other applications as well, I haven't checked all my apps, but File managers nemo and nautilus are working fine.  Also, before few months ago, I have included some windows fonts for my libre office shown . I used the copy (cp) method, not the link (ln -s). But, was working fine until yesterday. Haven't done any major change or update, at least on my Linux partition (dual boot). But, I don't think that this has anything to do with that.  Any idea how can I fix this issue?  . How to prove this binomial identity $\sum_{r=0}^n {r {n \choose r}} = n2^{n-1}$? WOL - Wake On Lan over internet I remember seeing an upper bound for the binomial $\binom{n}{k}$ with an exponential function, something like $\binom{n}{k}\leq \left(ne/k\right)^k$. What exactly is it, and are there other similar good upper bounds for $\binom{n}{k}$?  Edit: As the link in Macavity's comment shows, the bound is indeed $\binom{n}{k}\leq \left(ne/k\right)^k$. How can we prove this? Closed-form of $\int_0^1 \operatorname{Li}_p(x) \, dx$ I'm trying to find a way of building a new power supply for my workshop, in order to keep it small and not so hot I will be using a spare xformer to step down mains to 24v and then a variable buck converter to adjust it (and CC mode, displays and blinky stuff).   I thought it would be a good idea to use a linear regulator on the output stage to smooth things out, but I can't seem to think of a control scheme that allows me to change the voltage using only one potentiometer. The buck stage is this topology but with a external PNP transistor.(It has already been prototyped, it works alright, I know the mc34063A is old)   The only idea I got that ""works"" is using the buck converter output as a reference for a linear regulator (IC or discrete parts), but using a SMPS output as reference for anything is a bad idea, due to the amount of noise and fluctuations.   This is the sort of output stage I can and have built (or bought) over time. Just a big discrete regulator.  In short: How to control a MC34063A step down (buck) converter so it follows the output stage +1-3 V of headroom. ID a book about a mirror world and 4th dimension I read a book about 10-15 years ago about a boy and a girl who find a mirror. What made the mirror special was, they were able to enter the reflection and be a part of the reverse image world. They end up going to school and when asked to write something on the board, it ends up being backwards, but to them looks normal.  Later, the two end up in a world with 4 dimensions. With the added dimension they can't see as they normally could. If one moved a certain way the other would see their insides. Eventually a native of that dimension made some type of device that lets them see regularly.  Other than that my memory is blank. If I remember anything else I will be sure to edit it in. Check if wp-login is current page How can I check if the current page is wp-login.php or wp-signup.php ?  Are there more elegant solutions than using $_SERVER['REQUEST_URI'] ? WinterBash site exhibits some strange 404 behavior I was poking around winterba.sh for secret hats and I figured there may be a secret hat linked to a URL so I decided to look at some different URLs and got plenty of 404s but, some pages throw different 404s than others. Why?  Example:  throws the classic "Page Not Found" winterbash style... but  just has the text "404"  ( used to throw just the text "404" but since that has changed)  Still happening at 2016 with . Dynamic Comparison Operators in PHP How can I make Safari cmd+number shortcut switch tabs instead of opening the bookmark associated with that number? I'm used to switching tabs with cmd+x where x is a number and takes me to tab x in firefox and pretty much every other browser I've ever used. I like safari's speed and would like to try it a bit, but the cmd+x shortcut is burned in my brain and every time I use safari I end up screwing up. I'd like to know if its possible to change this behavior, because this simple thing is a stopper for me. Understanding dummy (manual or automated) variable creation in GLM When is the union of a family of subspaces of a vector space also a subspace? It is not difficult to prove that the union of a chain (or, more generally, a directed family) of subspaces of a vector space $V$ is a subspace of $V$.   Given a family $\mathcal{F}$ of subspaces of a vector space $V$ such that the union of $\mathcal{F}$ is a subspace of $V$, is it true that $\mathcal{F}$ is a directed family?  If not, is there a "nice" characterization of families of subspaces whose union is a subspace? What are "Commited Memory", "Cached", "Paged", "Not-paged pool" & How They are Different with "In-Use Memory" How do I enumerate the properties of a JavaScript object? How do I enumerate the properties of a JavaScript object?  I actually want to list all the defined variables and their values, but I've learned that defining a variable actually creates a property of the window object. I seem to remember from first year physics that we can calculate the RMS speed of a stationary, ideal gas with $v=\sqrt{\frac{3RT}{M}}$. Does a similar equation exist for liquids? Is empty set element of every set if it is subset of every set? This problem is from Discrete Mathematics and its Applications  My question is on 9b. I know that the sign represents an element is a member of. (from book)  I know that the O with a slash across it is the empty set which &quot;is a special set that has no elements&quot;. From , I got that the empty set is a subset of all sets, meaning that every member of the empty set(nothing) is also a member of any other set. Based on all of this, for 9b, would {0} contain the empty set because it fundamentally has the elements that consist of the empty set(nothing) or does it physically have to have the empty set? Error: the question could not be loaded When I was trying to open  I just added using the iOS app I received this error:     Error The question could not be loaded   Reproduction scenario:   add a question; in my case it didn't open it directly; it doesn't show up in the list yet; I opened my profile and clicked the question; bang! How do I fork a process that doesn't die when shell exits? Give users a way to see their "Positive Question Record" score