I'm currently learning polymorphism in Java, and part of the assignment was to create a program that will print out various subclasses using inheritance and polymorphism. I have tried looking for solutions but I couldn't seem to find anyone else experiencing this issue.  Below is a piece of code that is supposed to print Alex and Alexa respectively. However, the output is, instead, Alexa Alexa.  I have tried debugging by stepping through using Eclipse, but I can't pinpoint what is the mistake. I am truly stumped at this point, I've been trying this question for the past week but to no avail. Please forgive me if this is a simple question but I can't figure out what went wrong. I would truly appreciate any assistance!  import java.util.ArrayList; public class Human {    protected static String name;     public Human(String name) {        System.out.println("In human constructor");        this.name = name;    }    void greetings() {}     static void print(Human human) {        System.out.println(name);    }     public static void main(String[] args) {        ArrayList&lt;Human&gt; human = new ArrayList&lt;Human&gt;();        human.add(new Man("Alex"));        human.add(new Woman("Alexa"));        for (int i = 0; i &lt; human.size(); i++) {            print(human.get(i));        }    } }  class Man extends Human {     public Man(String name) {        super(name);        // TODO Auto-generated constructor stub    }  }  class Woman extends Human {     public Woman(String name) {        super(name);        // TODO Auto-generated constructor stub    }  }
To be specific, I was trying this code:  package hello;  public class Hello {      Clock clock = new Clock();      public static void main(String args[]) {         clock.sayTime();     } }   But it gave the error      Cannot access non-static field in static method main   So I changed the declaration of clock to this:  static Clock clock = new Clock();   And it worked. What does it mean to put that keyword before the declaration? What exactly will it do and/or restrict in terms of what can be done to that object?
$m$ doesn't come in the sequence $a_n=[n+\sqrt{n}+\frac{1}{2}]$ iff m is a perfect square Let $(a_n)$ be a sequence of positive integers defined by  $a_n=[n+\sqrt{n}+\frac{1}{2}]$  Show that a natural number $m$ doesn't occur in the sequence iff it is a square. I use tikz (and tikzpicture) a fair bit, but files that used to compile fine before the latest slew of updates to pgf, and pstricks, no longer seem to do so (at least, on my MikTeX installation). The MWE (below) seems to compile correctly, but the DVI can't be rendered using yap, and dvi -> ps -> pdf fails (the dvi -> ps seems to be ok -- to the extent it isn't throwing errors), but ps2pdf fails miserably, with the following errors:   Error: /undefined in XC@.  Operand stack:    --nostringval--   --nostringval--   --nostringval--   --nostringval--   -  -nostringval--   --nostringval-- Execution stack: %interp_exit   .runexec2   --nostringval--   --nostringval--   --  nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --  nostringval--   false   1   %stopped_push   2045   1   3   %oparray_pop    2044   1   3   %oparray_pop   2025   1   3   %oparray_pop   1884   1   3    %oparray_pop   --nostringval--   %errorexec_pop   .runexec2   --nostringval-  -   --nostringval--   --nostringval--   2   %stopped_push   --nostringval-- Dictionary stack:   --dict:979/1684(ro)(G)--   --dict:1/20(G)--   --dict:87/200(L)--   --    dict:182/300(L)--   --dict:58/200(L)--   Current allocation mode is local   Current file position is 99615   GPL Ghostscript 9.26: Unrecoverable error, exit code 1   Here is the MWE:  \documentclass[12pt,letterpaper,oneside]{article}  \usepackage{tikz}  \usetikzlibrary{decorations,shapes,arrows,matrix,positioning}  \begin{document}  \begin{center} \begin{tikzpicture}[x=0.175cm,y=0.175cm,scale=1]  % set up maximum and minimum x- and y-coordinates \def\xmin{0} \def\xmax{23.5} \def\ymin{0} \def\ymax{23.5}  % draw and label axes    \draw[-&gt;,thick] (\xmin,0) -- (\xmax,0) node[below=8pt,near end]  {\small{abundance ($N$)}};   \draw[-&gt;,thick] (0,\ymin) -- (0,\ymax) node[above=12pt,near   start,rotate=90] { \small{birth rate ($b$)}};  % draw vertical reference line at K/2=50   \draw[color=black, thick,  smooth] (0,20) -- (20,0)  node[below=6pt,midway,rotate=-45] {\small{slope~$=a$}};  % draw circle around point where function intersects x-axis \draw [red] (0,20)  ellipse (0.2cm and 0.2cm) node[right=3pt,black] {$b_0$};   \end{tikzpicture}  \end{center}   \end{document} Reflection to Identify Extension Methods If two people want to buy a car together, would they go half on the car or halves. Example: Let's go half on this car or Let's go halves on this car? PSTricks error "Undefined control sequence  \c@lor@to@ps" I have a problem with this file tex:  \begin{document} \begin{figure} \begin{center} \begin{pspicture}(0,0)(1,3.8) \psline{-&lt;}(0,0)(0,.2) \psline{-}(0,.2)(0,.4) \psline{*-&gt;}(0,.4)(0,.9) \psline{-*}(0,.9)(0,1.4) \psline{-&lt;}(0,1.4)(0,2.4) \psline{-}(0,2.4)(0,3.4) \psline{*-}(0,3.4)(0,3.6) \psline{&gt;-}(0,3.6)(0,3.8) \rput(1,.4){$y=0$}%testo \rput(1,1.4){$y=1$} \rput(1,3.4){$y=3$} \end{pspicture} \end{center} \caption{} \end{figure} \end{document}   but I don't understand where is the error. Let $X$ be an infinite dimensional Banach space. Prove that every Hamel basis of X is uncountable. Let $X$ be an infinite dimensional Banach space. Prove that every basis of $X$ is uncountable.  Can anyone help how can I solve the above problem? Does Windows 7 allow auto-login with a stored password, like TweakUI did? Show that $E(X)=\int_{0}^{\infty}P(X\ge x)\,dx$ for non-negative random variable $X$ The "New Contributor" dialog is masked The New Contributor dialog is masked from where the comment section ends. Here are some screenshots just to be more clear: With no comments:    With one comment:    No masking with more comments: How can I make a macOS Mojave bootable USB installer in Windows 10? Can I use the Unity launcher icon to minimize applications/windows? Organic yet accurate modeling with the golden spiral Foreword  First off, let me say that I am profoundly amazed at the orderliness in nature. If you haven't heard about the Fibonacci sequence (0, 1, 1, 2, 3, 5, 8, 13, ...), you should check it out.  This mathematical concept of the Fibonacci numbers can be shaped into a set of squares, where the lengths of the sides of the squares follow the Fibonacci sequence:     This is sometimes called a golden ratio. It can be formed into a (golden) spiral. (a.k.a. logarithmic spiral):      Application  I am looking for ways on how to utilize this concept in Blender. Primarily in organic modeling. The golden spiral is found all throughout nature. From flower seed heads, sea shells, and ram horns to hurricanes and spiral galaxies.  My question is: how can I model based off of one or multiple golden spirals? Specifically, I'm interested in modeling a sunflower head like the one in the following image. I'm mostly interested in the point of origin of the individual seeds (not worried about the shape). Does Blender have any features related to this? Replicate data from one list to another list sharepoint I have a list A with columns Emp ID, First name &amp; last name and list B wih column name Emp ID, First name, last name , phone number and address.  I want functionality such that when i enter item in List A and save same data should get copied in 3 columns of list B. Can someone help me with the approach. Thnks external variable in awk For $G$ a group and $H\unlhd G$, then $G$ is solvable iff $H$ and $G/H$ are solvable? I recently read the well known theorem that for a group $G$ and $H$ a normal subgroup of $G$, then $G$ is solvable if and only if $H$ and $G/H$ are solvable. In my book, only the fact that $G$ is solvable implies $H$ is solvable was proven. I was able to show that if $H$ and $G/H$ are solvable, then so is $G$, but I can't quite show that $G$ is solvable implies $G/H$ is solvable.   My idea was this. Since $G$ is solvable, there exists a normal abelian tower $$ G=G_0\supset G_1\supset\cdots\supset G_r=\{e\}. $$ I let $K_i=G_i/(H\cap G_i)$, in hopes of getting a sequence $$ G/H\supset K_1\supset\cdots\supset K_r=\{e\}. $$ My hunch is that the above is also a normal abelian tower. However, I'm having trouble verifying that $K_{i+1}\unlhd K_i$ and that $K_i/K_{i+1}$ is abelian.  Writing $H_i=H\cap G_i$, I take $gH_{i+1}\in K_{i+1}$ for some $g\in G_{i+1}$. If $g&#39;H_i\in K_i$, then I want to show $g&#39;H_igH_{i+1}g&#39;^{-1}H_i$ is still in $K_{i+1}$, but manipulating the cosets threw me off. I also tried to use either the second or third isomorphism theorems to show that $K_i/K_{i+1}$ is abelian, but I'm not clear on how to apply it exactly. I'd be grateful to see how this result comes through. Thank you. Using "of" or apostrophe, which is more common? Non abelian Lie group with abelian Lie algebra What are some scenarios where FTL information transfer would violate causality? I've always heard people saying, "Faster than light information transfer can't happen because it would violate causality!  Effects can precede their causes!"  However, I'm trying to think of a situation where this would happen.  I'm sure it has something to do with relativity or something like that.  I sort of understand that people going faster perceive time slower.  Can someone help illuminate this for me by showing a scenario where causality is clearly violated due to FTL information transfer? How do you make a torus 'telescope' open? For which complex $a,\,b,\,c$ does $(a^b)^c=a^{bc}$ hold?