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% Document Info
\author{Huluvu424242 (FunThomas424242)}
\pdfinfo{
  /Title (java-singleton.pdf)
  /Creator (Cheatography)
  /Author (Huluvu424242 (FunThomas424242))
  /Subject (Java Singleton Cheat Sheet)
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    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Java Singleton Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{Huluvu424242 (FunThomas424242)} via \textcolor{DarkBackground}{\uline{cheatography.com/19991/cs/3928/}}}
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  \vspace{-2pt}Huluvu424242 (FunThomas424242) \\
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  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Not Yet Published.\\
   Updated 12th May, 2016.\\
   Page {\thepage} of \pageref{LastPage}.
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  Measure your website readability!\\
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\mymulticolumn{1}{x{17.67cm}}{\bf\textcolor{white}{Diskussionsseiten}}  \tn
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\mymulticolumn{1}{x{17.67cm}}{1) \seqsplit{http://www.theserverside.de/singleton-pattern-in-java/} \newline % Row Count 2 (+ 2)
2) http://www.cs.umd.edu/\textasciitilde{}pugh/java/memoryModel/DoubleCheckedLocking.html \newline % Row Count 4 (+ 2)
3) \seqsplit{https://funthomas424242.wordpress.com/2012/02/19/cc-singleton-korrekt-implementieren/}% Row Count 6 (+ 2)
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\mymulticolumn{1}{x{17.67cm}}{\bf\textcolor{white}{Singleton - unsichere Initialisierung}}  \tn
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\mymulticolumn{1}{x{17.67cm}}{Diese Implementierung hat folgende Besonderheiten: \newline {[}1{]} Theoretisch funktioniert sie nicht - in der Praxis taugt sie aber als Signleton (siehe dazu folgende \{\{popup="http://www.bibsonomy.org/bibtex/20c33818a5d629b8f3fd9d4382334219f/funthomas424242"\}\}Diskussion\{\{/popup\}\}) \newline {[}2{]} Man darf sich hier bei Zugriff nicht auf ein korrekt initialisiertes Signleton verlassen, da im konkreten Fall auf Grund des Memory Modelles keine Annahmen darüber zugelassen sind wann die Felder des erzeugten Singleton wirklich alle korrekt befüllt und für jeden Thread konsistent lesbar sind. \newline  \newline public class Resource\{ \newline  private static Resource singleton; \newline public static Resource createInstance()\{ \newline    if(singleton==null)\{                                  //erster Test \newline     synchronized(Resource.class)\{ \newline       if(singleton==null)\{                              //zweiter Test \newline          singleton=new Resource(); \newline       \} //endif \newline      \} // end sync \newline    \}// endif \newline  return singleton;  \newline  \} \newline \}} \tn 
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\mymulticolumn{1}{x{17.67cm}}{Details zum Problem unter: http://www.cs.umd.edu/\textasciitilde{}pugh/java/memoryModel/DoubleCheckedLocking.html}  \tn 
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\mymulticolumn{1}{x{17.67cm}}{\bf\textcolor{white}{Singleton - korrekte Intialisierung}}  \tn
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\mymulticolumn{1}{x{17.67cm}}{private static volatile Resource resource; \newline private static volatile Resource singleton; \newline public static Resource createInstance()\{ \newline  if(resource==null)\{ \newline   synchronized(Resource.class)\{ \newline    if(singleton==null)\{ \newline        singleton=new Resource(); \newline    \} \newline   \} \newline   resource=singleton; \newline  \} \newline  return resource; \newline \}} \tn 
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\mymulticolumn{1}{x{17.67cm}}{Ähnliche L{\"o}sungen werden auch hier diskutiert: \seqsplit{http://www.angelikalanger.com/Articles/EffectiveJava/41.JMM-DoubleCheck/41.JMM-DoubleCheck.html}}  \tn 
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