I am trying to use Spring Boot to read a file stored in GCS using this tutorial:  My code as follows: Resource gcsFile = resourceLoader.getResource(gcsPath);             //InputStream inputStream = gcsFile.getInputStream();             return StreamUtils.copyToString(                     gcsFile.getInputStream(),                     StandardCharsets.UTF_8);  resourceLoader is injected as a dependency using @Autowired annotation. The gcsPath variable is a String to the gcs file location (example: gs://REPLACE_WITH_YOUR_BUCKET/my-file.txt). I get the below exception: java.lang.NullPointerException: null         at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:878)         at com.google.cloud.storage.BlobId.of(BlobId.java:109)         at org.springframework.cloud.gcp.storage.GoogleStorageResource.getBlobId(GoogleStorageResource.java:108)         at org.springframework.cloud.gcp.storage.GoogleStorageResource.resolve(GoogleStorageResource.java:113)         at org.springframework.cloud.gcp.storage.GoogleStorageResource.getInputStream(GoogleStorageResource.java:167)   During debugging, I found that the following line is what triggers this exception: InputStream inputStream = gcsFile.getInputStream(); I have not been able to figure out how and why this is happening. Can someone please help?
What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?
Defining macros with arguments With newcommand I can define customized command like \ABC. Is there any way to define a command with arguments. For example I want \brat{A}{B} be the same as [\![A,B]\!]. Show that the determinant of $A$ is equal to the product of its eigenvalues Show that the determinant of a matrix $A$ is equal to the product of its eigenvalues $\lambda_i$.   So I'm having a tough time figuring this one out. I know that I have to work with the characteristic polynomial of the matrix $\det(A-\lambda I)$. But, when considering an $n \times n$ matrix, I do not know how to work out the proof. Should I just use the determinant formula for any $n \times n$ matrix? I'm guessing not, because that is quite complicated. Any insights would be great. What's the difference between  and ,  and ? Is it only red, green and blue that can make up any color through additive mixture? I'm reading about color vision and have some trouble understanding the motivation for why the  was suggested in the first place. The book I'm reading ("Psychgology: The science of mind and behavior") states:     At the beginning of the nineteenth century it was discovered that any colour in the visible spectrum could be produced by some combination of the wavelenghts that corresponds to the colours blue, green and red in what is known as additive color mixture.   From the explanation in the book, it seems like this somehow should be a reason for also supposing that the human retina was composed of cones sensitive to the colors green, red and blue respectively. I guess this would be a valid argument if it was only red, green and blue that, through additive mixture, could make up any color.  Is it only red, green and blue that, through additive mixture, can make up any color? Why so many pins for the MOSFET's drain? When writing dates in prose in the dmy format (29 March 2014), is the correct preposition "in" or "on". I'm seeing it with "in" , but that construction is foreign to me.     It was released in 29 March 2010 on Steam for Microsoft Windows, and in 25 March 2010 on Xbox Live Indie Games for the Xbox 360.    "On" would seem to make more sense, from what I know. Verdict? One very convenient property of $\mathbb{R}$ as a ring is that there is an upper bound for the degree of irreducible polynomials in $\mathbb{R}[x]$, as      If $f\in\mathbb{R}[x]$ has degree larger than $2$, then $f$ is reducible.   However, the proof as I know depends highly on the fact that $\mathbb{C}$ is algebraically closed, and the very nice property: $z\in\mathbb{C}$ is in $\mathbb{R}$ if and only if $z=\bar{z}$.  This makes a generalization to other integral domains rather difficult. So the problem is      For what kind of integral domain $R$, we have a finite upper bound on the degree of irreducible elements in $R[x]$?   Some most familiar examples are ruled out: in $\mathbb{Z}[x]$, $\mathbb{Q}[x]$ and $\mathbb{F}_{p}[x]$, there is not such a bound. Unfortunately these exhaust all integral domains about which I have a working knowledge.  Another result might help is , which says if we can find a prime ideal $\mathfrak{p}$ in $R$ such that $\mathfrak{p}^2\neq\mathfrak{p}$, then by picking $a\in\mathfrak{p}^2\backslash\mathfrak{p}$ we have an irreducible $a+x^d$, where $d$ can be arbitrary, and hence the upper bound is not possible.  So we only need to focus on domains where $\mathfrak{p}^2=\mathfrak{p}$ for all prime ideals. This seems to be a quite strong restriction but I am not sure what to make of it.  Can someone give a hint?  Thanks! Prove $$\det(e^A) = e^{\operatorname{tr}(A)}$$ for all matrices $A \in \mathbb{C}_{n×n}$. Wifi losing connection, weak signal, Intel 7260 adapter I yesterday upgraded from Windows to Ubuntu 15.04 but I have problem with my wireless adapter Intel Corporation Wireless 7260 (rev 73). It randomly loses internet connection. Restarting adapter always helps. (same it did with Windows, except that sometimes restarting adapter didn't help).   Additionally, I have weaker connection then I had with Windows.  Thank you! Toy Line (Production) Run I am not sure about the meaning of this:          Transformers: Generation 1 (also known as Generation One or G1) was a children's toy line that ran from 1984 to 1991 and was produced by Hasbro.     Would the following rewrite be better?        Transformers: Generation 1 (also known as Generation One or G1) was a children's toy line the production of which ran from 1984 to 1991 and was produced by Hasbro. I recently put a bounty on a question regarding the . I did this as the only two answers on that page are not satisfactory and I wish to encourage a tractable answer.  I am concerned that when the bounty period expires, if I do not select an answer for the bounty that it may be awarded automatically to one of these speculative and unsatisfactory answers. How might I prevent that? I could put an answer of my own stating "no satisfactory sources are available" and award the bounty to that, however I feel that there should be a better way.  I stress that I put the bounty on the question specifically because the current answers are not satisfactory and I do not want to award them. Word for "someone who talks too much" How is canonicity of derivative works determined for Star Wars? Disabling module with config sync and removing with composer I have an issue disabling modules, I've searched but cannot find something useful:  - Developer A disable module and via composer remove it  - I pull his changes so i run composer install that remove the code, then drush cim to update configuration, but it complains that the module is missing while it's trying to delete its configurations.  What's the right way to do this? I can't import config before running composer install because along the uninstalled module there could be also new modules needed for the configuration import. Two homologous but not homotopic loops on a closed surface of genus greater than one Suppose $S$ is a closed surface with genus greater than $1$. Give an example of two loops on $S$ which are not homotopic, but are homologous to each other.   I need help solving this question. I have read the Wikipedia page on it and I realize that it does not contain the necessary knowledge to visualize this problem.  And I was also wondering the relation between the fundamental group $\pi_1(S)$ and the first homology group $H_1(S)$? Some restrictions is that $S$ is a closed surface and the genus is greater than $1$. Downgrade nVidia Shield to Android 4.4 KitKat "POSSIBLE BREAK-IN ATTEMPT!" in /var/log/secure — what does this mean? I've got a CentOS 5.x box running on a VPS platform. My VPS host misinterpreted a support inquiry I had about connectivity and effectively flushed some iptables rules.  This resulted in ssh listening on the standard port and acknowledging port connectivity tests. Annoying.   The good news is that I require SSH Authorized keys.  As far as I can tell, I don't think there was any successful breach.  I'm still very concerned about what I'm seeing in /var/log/secure though:     Apr 10 06:39:27 echo sshd[22297]: reverse mapping checking getaddrinfo for 222-237-78-139.tongkni.co.kr failed - POSSIBLE BREAK-IN ATTEMPT! Apr 10 13:39:27 echo sshd[22298]: Received disconnect from 222.237.78.139: 11: Bye Bye Apr 10 06:39:31 echo sshd[22324]: Invalid user edu1 from 222.237.78.139 Apr 10 06:39:31 echo sshd[22324]: reverse mapping checking getaddrinfo for 222-237-78-139.tongkni.co.kr failed - POSSIBLE BREAK-IN ATTEMPT! Apr 10 13:39:31 echo sshd[22330]: input_userauth_request: invalid user edu1 Apr 10 13:39:31 echo sshd[22330]: Received disconnect from 222.237.78.139: 11: Bye Bye Apr 10 06:39:35 echo sshd[22336]: Invalid user test1 from 222.237.78.139 Apr 10 06:39:35 echo sshd[22336]: reverse mapping checking getaddrinfo for 222-237-78-139.tongkni.co.kr failed - POSSIBLE BREAK-IN ATTEMPT! Apr 10 13:39:35 echo sshd[22338]: input_userauth_request: invalid user test1 Apr 10 13:39:35 echo sshd[22338]: Received disconnect from 222.237.78.139: 11: Bye Bye Apr 10 06:39:39 echo sshd[22377]: Invalid user test from 222.237.78.139 Apr 10 06:39:39 echo sshd[22377]: reverse mapping checking getaddrinfo for 222-237-78-139.tongkni.co.kr failed - POSSIBLE BREAK-IN ATTEMPT! Apr 10 13:39:39 echo sshd[22378]: input_userauth_request: invalid user test Apr 10 13:39:39 echo sshd[22378]: Received disconnect from 222.237.78.139: 11: Bye Bye     What exactly does "POSSIBLE BREAK-IN ATTEMPT" mean?  That it was successful? Or that it didn't like the IP the request was coming from? For $n\geq 3$ there exist $x,y\in S_n$ such that $x$ and $y$ have order $2$ and $xy$ has order $n$. Assume that $n\geq 3$. Let $S_n$ be the symmetric group with $n!$ elements. Prove that there exists $x$ and $y$ in $S_n$ such that $x$ and $y$ have order $2$ and $xy$ has order $n$.  For $n=3$, it is easy to see that $x=(1, 2)$ and $y=(1, 3)$ works. How to prove it for the general case? Inequality involving $\limsup$ and $\liminf$: $ \liminf(a_{n+1}/a_n) \le \liminf((a_n)^{(1/n)}) \le \limsup((a_n)^{(1/n)}) \le \limsup(a_{n+1}/a_n)$ This may have been asked before, however I was unable to find any duplicate. This comes from  of "Mathematical Analysis: An Introduction" by Browder. Problem 14:     If $(a_n)$ is a sequence in $\mathbb R$ and $a_n &gt; 0$ for every $n$. Then show:   $$ \liminf(a_{n+1}/a_n) \le \liminf((a_n)^{(1/n)}) \le \limsup((a_n)^{(1/n)}) \le \limsup(a_{n+1}/a_n)$$   The middle inequality is clear. However I am having a hard time showing the ones on the left and right. (It seems like the approach should be similar for each). This is homework, so it'd be great if someone could give me a hint to get started on at least one of the inequalities.  Thanks. How to find the frequency and type of my current RAM? How shall I find out the frequency and type of my current RAM? My OS is Ubuntu 12.04.