JavaFX parameter passed to new window becomes NULL
What is a NullPointerException, and how do I fix it?
Two blue arrows at top right of icons I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question: Increment value based on grouped field How to highlight important parts (with a gray background) In the below link        the author highlights anything which is important using a greyish color background. For example, if you see Equation 1.5.3 (which on page 22 of the book) it is highlighted in grey. I would like to know the TeX commands for producing similar output. Find the radius of the inscribed circle of a right triangle. Find the radius of the inscribed circle of a right triangle. The triangle's height is $\sqrt{6} + \sqrt{2}$ while the bisector of the right angle is 4.  This seemed like a generic similar triangles problem but it isn't that simple when I tried to solve it. Any help?  EDIT: Here is a picture of the problem What do the X and Y axis stand for in the Fourier transform domain? I am hearing my screen The following could have shown up as an exercise in a basic Abstract Algebra text, and if anyone can give me a reference, I will be most grateful.  Consider a set $X$ with an associative law of composition, not known to have an identity or inverses. Suppose that for every $g\in X$, there is a unique $x\in X$ with $gxg=g$. Show that $X$ is a group.  Note that I’m not asking for a proof (though a really short one would please me!), just some place where this has been published. Does "a couple" always mean two? How to prove that a set is invariant? What's the typical microclimate in the aircraft passenger cabin? I am trying to find a book (young adult) where the devil is the protaganist, and other gods appear as characters I believe it was written by a teenager, and might have a sequel.   It has been many years since I read it, but I believe it had the devil acting like a regular human. He wasn't evil. I think it incorporated a lot of (gods/characters) norse, roman, Christian, and pagan. Using same modulus for RSA How to generate world files for raster X? Rule of thumb for number of bootstrap samples I wonder if someone knows any general rules of thumb regarding the number of bootstrap samples one should use, based on characteristics of the data (number of observations, etc.) and/or the variables included? Accelerating electrons via microwaves In Synchrotrons I think they use microwaves to accelerate the electrons bundles that fly through-how does putting a microwave through a cavity accelerate an electron? I know that the Electric and Magnetic fields could and do have an effect on the electron, but if the radiation is moving parallel to the electron, wouldn't the force be perpendicular? Also, how exactly does the microwave radiation look in the vacuum chamber? Are the two ends constant nodes? Where do AirDrop files go when I transfer them between an iPad, iPhone and iPod? I AirDropped some Google Docs from my iPad to my iPhone but nothing happened; where did my files go? The file was a list of tools. How do I navigate to a samba location I've mounted in Nautilus on the command line? Please note: I am two weeks old in Linux. I have found a lot of answers to this question on the internet, tried many, but all failed one way or another. Therefore I dare to ask once again in the hope that someone here could explain it simply :)  Pre-conditions:  In my institute, we have a Samba server. In Windows, it is accessed by going to \\xyz.220.131.233\ and entering the login abc and the password def.   In Ubuntu, I was able to do exactly the same using Nautilus, pressing Ctrl+L and entering smb://xyz.220.131.233/. It then asks for the login and the password and connects. I can even drag a folder from here to the 'Places' and have a shortcut to the remote location.   So far so good. I've just installed Matlab and want to open this remote location. Trying to cd to smb://xyz.220.131.233/ returns      Cannot CD to smb://xyz.220.131.233 (Name is nonexistent or not a directory).   A Mac user in my group told me I first mount the location, but he didn't know how to do it.   Is it true and how do I do it? How to model the bottle threads? The picture show the threads I want to create on the highlighted object. Problem is I don't know how and tutorials really haven't helped much as most of them seem to be about creating a bolt. So I was hoping I could get some help on how to do this efficiently.While keeping the top flat like a water bottle. The picture shows the threads I'm after. Looking for a Pre-1975, young adult, sci-fi, colored circle dimension crossing Looking for the title and or author of a long ago favorite; I have searched the web for it on and off for years.  I read a paperback novel about 40 years ago; it was probably a used book at that time. Probably pre-1975 publication.  In my memory it was written in the style of Andre Norton I have looked through her , but I am not finding it. It was a young adult sci-fi novel.  Plot; a young woman (gender was not strong, but I remember the main character being female) can see different colored circles floating around. When she looks at them just right, she can jump through to another universe.  In the other universe, things change.  She might become a lion, or maybe she is carrying a seed that becomes a net in the other universe.   Two bad guys are chasing her around the different dimensions, I recall one scene where they are all sliding down an icy slope and she jumps through a portal, to escape the bad guys.   There were a lot of complexities about, dimensions, what became what, different colors of portals and such.