What is an uber jar

Question

I am reading Maven documentation and came across the name  uber-jar     What does an uber-jar mean and what are its features advantages

User · Answer

The different names are just ways of packaging java apps.

Skinny – Contains ONLY the bits you literally type into your code editor, and NOTHING else.

Thin – Contains all of the above PLUS the app’s direct dependencies of your app (db drivers, utility libraries, etc).

Hollow – The inverse of Thin – Contains only the bits needed to run your app but does NOT contain the app itself. Basically a pre-packaged “app server” to which you can later deploy your app, in the same style as traditional Java EE app servers, but with important differences.

Fat/Uber – Contains the bit you literally write yourself PLUS the direct dependencies of your app PLUS the bits needed to run your app “on its own”.

Source: Article from Dzone

Reposted from: https://stackoverflow.com/a/57592130/9470346

User · Answer

ber is the German word for above or over  it s actually cognate with the English over    Hence  in this context  an uber-jar is an  over-jar   one level up from a simple JAR  a   defined as one that contains both your package and all its dependencies in one single JAR file  The name can be thought to come from the same stable as ultrageek  superman  hyperspace  and metadata  which all have similar meanings of  beyond the normal    The advantage is that you can distribute your uber-jar and not care at all whether or not dependencies are installed at the destination  as your uber-jar actually has no dependencies   All the dependencies of your own stuff within the uber-jar are also within that uber-jar  As are all dependencies of those dependencies  And so on      a  I probably shouldn t have to explain what a JAR is to a Java developer but I ll include it for completeness  It s a Java archive  basically a single file that typically contains a number of Java class files along with associated metadata and resources

User · Answer

Paxdiablo s definition is really good  In addition  please consider delivering an uber-jar is sometimes quite useful  if you really want to distribute a software and don t want customer to download dependencies by themselves  As a draw back  if their own policy don t allow usage of some library  or if they have to bind some extra-components  slf4j  system compliant libs  arch specialiez libs       this will probably increase difficulties for them  You can perform that    basically with maven-assembly-plugin a bit more further with maven-shade-plugin  A cleaner solution is to provide their library separately  maven-shade-plugin has preconfigured descriptor for that  This is not more complicated to do  with maven and its plugin   Finally  a really good solution is to use an OSGI Bundle  There is plenty of good tutorials on that    For further configuration  please read those topics    Should you provide dependent libraries in client jar  Best practices in building and deploying Clojure applications  good tutorials

User · Answer

A self-contained  executable Java archive  In the case of WildFly Swarm uberjars  it is a single  jar file containing your application  the portions of WildFly required to support it  an internal Maven repository of dependencies  plus a shim to bootstrap it all  see this

User · Answer

ubar jar is also known as fat jar i e  jar with dependencies  There are three common methods for constructing an uber jar     Unshaded  Unpack all JAR files  then repack them into a single JAR  Works with Java s default class loader  Tools maven-assembly-plugin Shaded  Same as unshaded  but rename  i e    shade   all packages of all dependencies  Works with Java s default class loader  Avoids some  not all  dependency version clashes  Tools maven-shade-plugin   JAR of JARs  The final JAR file contains the other JAR files embedded within  Avoids dependency version clashes  All resource files are preserved  Tools  Eclipse JAR File Exporter   for more

User · Answer

According to uber-JAR Documentation Approaches  There are three common methods for constructing an uber-JAR  Unshaded Unpack all JAR files  then repack them into a single JAR  Tools  Maven Assembly Plugin  Classworlds Uberjar Shaded Same as unshaded  but rename  i e    quot shade quot   all packages of all dependencies  Tools  Maven Shade Plugin JAR of JARs The final JAR file contains the other JAR files embedded within  Tools  Eclipse JAR File Exporter  One-JAR

User · Answer

For Java Developers who use SpringBoot    BER FAT JAR is normally the final result of the package phase of maven  or build task if you use gradle   Inside the Fat JAR one can find a META-INF directory inside which the MANIFEST MF file lives with all the info regarding the Main class  More importantly  at the same level of META-INF directory you find the BOOT-INF directory inside which the directory lib lives and contains all the  jar files that are the dependencies of your application

[maven] What is an uber jar?

The different names are just ways of packaging java apps.

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