Can a dropwizard application run on all operating systems on which java is supported. - dropwizard

Can a dropwizard application run on all operating systems on which java is supported. Is there a list of OS on which dropwizard is supported.

Drop-wizard is a java application, which runs on JVM(java virtual machine), which is supported by almost all the operating system.
So if your operating system supports JVM then it you are good to run your DW(dropwizrd) application on it.

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jenkins installation in Solaris server

How to install the jenkins on a solaris server? i found articles that this cannot be done as jenkins has discontinued support for solaris.
Even though official IPS repositories for Solaris are discontinued, you can still run Jenkins in Solaris via the jenkins webapp (jenkins.war). To quote from Jenkins installation doc:
Solaris, OmniOS, SmartOS, and other siblings
Generally it should
suffice to install Java 8 and download the jenkins.war and run it as a
standalone process or under an application server such as Apache
Tomcat.
Some caveats apply:
Headless JVM and fonts: For OpenJDK builds on minimalized-footprint
systems, there may be issues running the headless JVM, because Jenkins
needs some fonts to render certain pages.
ZFS-related JVM crashes: When Jenkins runs on a system detected as a
SunOS, it tries to load integration for advanced ZFS features using
the bundled libzfs.jar which maps calls from Java to native libzfs.so
routines provided by the host OS. Unfortunately, that library was made
for binary utilities built and bundled by the OS along with it at the
same time, and was never intended as a stable interface exposed to
consumers. As the forks of Solaris legacy, including ZFS and later the
OpenZFS initiative evolved, many different binary function signatures
were provided by different host operating systems - and when Jenkins
libzfs.jar invoked the wrong signature, the whole JVM process crashed.
A solution was proposed and integrated in jenkins.war since weekly
release 2.55 (and not yet in any LTS to date) which enables the
administrator to configure which function signatures should be used
for each function known to have different variants, apply it to their
application server initialization options and then run and update the
generic jenkins.war without further workarounds. See the libzfs4j Git
repository for more details, including a script to try and "lock-pick"
the configuration needed for your particular distribution (in
particular if your kernel updates bring a new incompatible libzfs.so).
Also note that forks of the OpenZFS initiative may provide ZFS on
various BSD, Linux, and macOS distributions. Once Jenkins supports
detecting ZFS capabilities, rather than relying on the SunOS check,
the above caveats for ZFS integration with Jenkins should be
considered.

What's the point of running an OS (Ubuntu) in Docker?

I have trouble understanding this concept. I know a little bit about how Docker works and what the benefits are, and while I understand running web servers, databases and development environments in containers, I don't understand the point of running an OS like Ubuntu in Docker.
Can someone explain why you would want to do that and also the benefits of an entire OS in a container?
The OS is essentially the runtime environment required to run your app. If you app is compiled to run on Linux, it relies on Linux libraries (libc, glib, and so on) that must be present in executing environment, regardless of its type. Docker makes no exception to this.
So a Ubuntu application requires a Ubuntu image in order to run correctly.
Note that Docker container does not include nor run an entire OS, but only the minimum set of libraries that allow your app to run. In particular it does never contain or execute a kernel, as it runs under the host kernel.
Docker doesn't have its own OS, it is installed on a machine and this allows it to share host operating system resources. There will be only one OS and all the containers will be using that OS.
Most of the application are meaningless without OS since it is required for IO, hardware calls etc.
Each docker container may have different packages (java, python, jboss etc), applications installed.

How do i know my CPU supports Docker?

What are now Docker cpu requirements for running in Linux, say, Ubuntu and Windows?
Is VT-x/AMD-v is enough or VT-d/AMD-Vi is required too?
Does it require MMU virtualization (Intel's Extended Page Tables (EPT) and Unrestricted Mode, and AMD's Nested Page Tables (NPT) and Rapid Virtualization Indexing (RVI)) like Hyper-V?
Would Xeons with VT-x like 53xx, 54xx run both 32-bit and 64-bit docker images, or just 32-bit or none of them in say, Ubuntu?
May be there is some tool to check for compatibility?
Containers aren't virtual machines. VT-x is not required to run a container. Docker require's certain Linux kernel features. If you have a Linux system on a 3.10+ kernel and a x86-64 CPU, you can run Docker 17.09+.
Windows Server containers require Windows Server build 1709, Windows Server 2016 (Core and with Desktop Experience) and Windows 10 Professional and Enterprise (Anniversary Edition) (all 64bit).
If you want to use Hyper-V Containers, which provide more isolation than Windows Server containers, then you will need to meet Hyper-V's virtualisation requirements.

Does standard library refer to the whole API or just a package? [duplicate]

This question's answers are a community effort. Edit existing answers to improve this post. It is not currently accepting new answers or interactions.
Which one should I install when I want to start learning Java? I'm going to start with some basics, so I will write simple programs that create files, directories, edit XML files and so on, nothing too complex for now.
I guess Java SE (Standard Edition) is the one I should install on my Windows 7 desktop. I already have Komodo IDE which I will use to write the Java code.
Java SE = Standard Edition. This is the core Java programming platform. It contains all of the libraries and APIs that any Java programmer should learn (java.lang, java.io, java.math, java.net, java.util, etc...).
Java EE = Enterprise Edition. From Wikipedia:
The Java platform (Enterprise Edition) differs from the Java Standard
Edition Platform (Java SE) in that it adds libraries which provide
functionality to deploy fault-tolerant, distributed, multi-tier Java
software, based largely on modular components running on an
application server.
In other words, if your application demands a very large scale, distributed system, then you should consider using Java EE. Built on top of Java SE, it provides libraries for database access (JDBC, JPA), remote method invocation (RMI), messaging (JMS), web services, XML processing, and defines standard APIs for Enterprise JavaBeans, servlets, portlets, Java Server Pages, etc...
Java ME = Micro Edition. This is the platform for developing applications for mobile devices and embedded systems such as set-top boxes. Java ME provides a subset of the functionality of Java SE, but also introduces libraries specific to mobile devices. Because Java ME is based on an earlier version of Java SE, some of the new language features introduced in Java 1.5 (e.g. generics) are not available.
If you are new to Java, definitely start with Java SE.
Here are some differences in terms of APIs
Java SE includes has the following APIs and many more
applet
awt
rmi
jdbc
swing
collections
xml binding
JavaFX (Merged to Java SE 8)
Java 8 Collections Streaming API
Java 9 Reactive Streams API
Java 9 HTTP/2 API
Java EE includes the following APIs and many more
servlet
websocket
java faces
dependency injection
ejb
persistence
transaction
jms
batch api
Java ME includes the following APIs and many more
Wireless Messaging
Java ME Web Services
Security and Trust Services API
Location
Mobile XML API
Hope this helps.
Java SE is the foundation on which Java EE is built.
Java ME is a subset of SE for mobile devices.
So you should install Java SE for your project.
According to the Oracle's documentation, there are actually four Java platforms:
Java Platform, Standard Edition (Java SE)
Java Platform, Enterprise Edition (Java EE)
Java Platform, Micro Edition (Java ME)
JavaFX
Java SE is for developing desktop applications and it is the foundation for developing in Java language. It consists of development tools, deployment technologies, and other class libraries and toolkits used in Java applications. Java EE is built on top of Java SE, and it is used for developing web applications and large-scale enterprise applications. Java ME is a subset of the Java SE. It provides an API and a small-footprint virtual machine for running Java applications on small devices. JavaFX is a platform for creating rich internet applications using a lightweight user-interface API. It is a recent addition to the family of Java platforms.
Strictly speaking, these platforms are specifications; they are norms, not software.
The Java Platform, Standard Edition Development Kit (JDK) is an official implementation
of the Java SE specification, provided by Oracle. There are also other implementations, like OpenJDK and IBM's J9.
People new to Java download a JDK for their platform and operating system (Oracle's JDK is available for download
here.)
As I come across this question, I found the information provided on the Oracle's tutorial very complete and worth to share:
The Java Programming Language Platforms
There are four platforms of the Java programming language:
Java Platform, Standard Edition (Java SE)
Java Platform, Enterprise Edition (Java EE)
Java Platform, Micro Edition (Java ME)
JavaFX
All Java platforms consist of a Java Virtual Machine (VM) and an
application programming interface (API). The Java Virtual Machine is a
program, for a particular hardware and software platform, that runs
Java technology applications. An API is a collection of software
components that you can use to create other software components or
applications. Each Java platform provides a virtual machine and an
API, and this allows applications written for that platform to run on
any compatible system with all the advantages of the Java programming
language: platform-independence, power, stability,
ease-of-development, and security.
Java SE
When most people think of the Java programming language, they think of
the Java SE API. Java SE's API provides the core functionality of the
Java programming language. It defines everything from the basic types
and objects of the Java programming language to high-level classes
that are used for networking, security, database access, graphical
user interface (GUI) development, and XML parsing.
In addition to the core API, the Java SE platform consists of a
virtual machine, development tools, deployment technologies, and other
class libraries and toolkits commonly used in Java technology
applications.
Java EE
The Java EE platform is built on top of the Java SE platform. The Java
EE platform provides an API and runtime environment for developing and
running large-scale, multi-tiered, scalable, reliable, and secure
network applications.
Java ME
The Java ME platform provides an API and a small-footprint virtual
machine for running Java programming language applications on small
devices, like mobile phones. The API is a subset of the Java SE API,
along with special class libraries useful for small device application
development. Java ME applications are often clients of Java EE
platform services.
JavaFX
JavaFX is a platform for creating rich internet applications using a
lightweight user-interface API. JavaFX applications use
hardware-accelerated graphics and media engines to take advantage of
higher-performance clients and a modern look-and-feel as well as
high-level APIs for connecting to networked data sources. JavaFX
applications may be clients of Java EE platform services.
I guess Java SE (Standard Edition) is the one I should install on my
Windows 7 desktop
Yes, of course. Java SE is the best one to start with. BTW you must learn Java basics. That means you must learn some of the libraries and APIs in Java SE.
Difference between Java Platform Editions:
Java Micro Edition (Java ME):
Highly optimized runtime environment.
Target consumer products (Pagers, cell phones).
Java ME was formerly known as Java 2 Platform, Micro Edition or
J2ME.
Java Standard Edition (Java SE):
Java tools, runtimes, and APIs for developers writing, deploying, and running applets and applications. Java SE was formerly known as Java 2 Platform, Standard Edition or J2SE. (everyone/beginners starting from this)
Java Enterprise Edition(Java EE):
Targets enterprise-class server-side applications. Java EE was formerly known as Java 2 Platform, Enterprise Edition or J2EE.
Another duplicated question for this question.
Lastly, about J.. confusion
JVM (Java Virtual Machine):
JVM is a part of both the JDK and JRE that translates Java byte codes and executes them as native code on the client machine.
JRE (Java Runtime Environment):
It is the environment provided for the java programs to get executed. It contains a JVM, class libraries, and other supporting files. It does not contain any development tools such as compiler, debugger and so on.
JDK (Java Development Kit):
JDK contains tools needed to develop the java programs (javac, java, javadoc, appletviewer, jdb, javap, rmic,...) and JRE to run the program.
Java SDK (Java Software Development Kit):
SDK comprises a JDK and extra software, such as application servers, debuggers, and documentation.
Java SE:
Java platform, Standard Edition (Java SE) lets you develop and deploy Java applications on desktops and servers (same as SDK).
J2SE, J2ME, J2EE
Any Java edition from 1.2 to 1.5
Read more about these topics:
Differences between JDK and Java SDK
Java JDK, SDK, SE?
What is the difference between JVM, JDK, JRE & OpenJDK?
Yes, Java SE is where to start. All the tasks you mention can be handled with it.
Java ME is the Mobile Edition, and EE is Enterprise Edition; these are specialized / extended versions of Standard Edition.
Java SE (Standard Edition) is for building desktop apps.
Java ME (Micro Edition) is for old mobile devices.
Java EE (Enterprise Edition) is for developing web based applications.
Yes, you should start with Java SE. Java EE is for web applications and Java ME is for mobile applications--both of these build off of SE.
Developers use different editions of the Java platform to create Java programs that run on desktop
computers, web browsers, web servers, mobile information devices (such as feature phones), and
embedded devices (such as television set-top boxes).
Java Platform, Standard Edition (Java SE): The Java platform for developing
applications, which are stand-alone programs that run on desktops. Java SE is
also used to develop applets, which are programs that run in web browsers.
Java Platform, Enterprise Edition (Java EE): The Java platform for developing
enterprise-oriented applications and servlets, which are server programs that
conform to Java EE’s Servlet API. Java EE is built on top of Java SE.
Java Platform, Micro Edition (Java ME): The Java platform for developing
MIDlets, which are programs that run on mobile information devices, and Xlets,
which are programs that run on embedded devices.
If I were you I would install the Java SE SDK. Once it is installed make sure you have the JAVA_HOME environment variable set and add the %JAVA_HOME%\bin dir to your path.
Java SE is use for the desktop applications and simple core functions. Java EE is used for desktop, but also web development, networking, and advanced things.
EE:- Enterprise Edition:- This Java edition is specifically designed for enterprise applications/business where we have to deal with number of different servers with importance on security, transaction management etc.
SE:- Standard Edition:- This edition is for standard applications.
ME:- Micro Edition:- This java edition is specifically designed for mobile phone platforms. Where more importance is given on memory management as there is limited memory resources in mobiles .
So basically JAVA has different editions for different requirements.
The SE(JDK) has all the libraries you will ever need to cut your teeth on Java.
I recommend the Netbeans IDE as this comes bundled with the SE(JDK) straight from Oracle.
Don't forget to set "path" and "classpath" variables especially if you are going to try command line.
With a 64 bit system insert the "System Path" e.g. C:\Program Files (x86)\Java\jdk1.7.0 variable before the C:\Windows\system32; to direct the system to your JDK.
hope this helps.

Neo4j supports Windows but the recommended filesystem is ext4

The Neo4j manual shows that windows is supported, but the minimum filesystem is Ext4, what are the compromises for NTFS.
Neo4J is written on java and uses JDK abstraction of file system. So developers can recommend you some operation system, but theoretically it will work on FAT or even on proprietary OS of your cooler (if it is run with Java control).
Just provide your own measurement of performance at possible target OS and select best one.

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