I am working in spring boot and I saw properties tag in pom.xml file but I don't understand what does it mean and what can we do in this tag.
properties tag for e.g.
<properties> <java.version>1.8</java.version> </properties>What does properties tag mean ?
What can I add also in properties tag ?
11 Answer
What does properties tag mean ?
From Official Maven Docs :
Properties are the last required piece to understand POM basics. Maven properties are value placeholders, like properties in Ant. Their values are accessible anywhere within a POM by using the notation ${X}, where X is the property. Or they can be used by plugins as default values, for example:
In your case you have defined properties as version of java.
Now this property(java.version) can be reused later in maven pom file.
From Official Maven Docs :
They come in five different styles:
env.X: Prefixing a variable with "env." will return the shell's environment variable. For example, ${env.PATH} contains the PATH environment variable. Note: While environment variables themselves are case-insensitive on Windows, lookup of properties is case-sensitive. In other words, while the Windows shell returns the same value for %PATH% and %Path%, Maven distinguishes between ${env.PATH} and ${env.Path}. The names of environment variables are normalized to all upper-case for the sake of reliability.
project.x: A dot (.) notated path in the POM will contain the corresponding element's value. For example: 1.0 is accessible via ${project.version}.
settings.x: A dot (.) notated path in the settings.xml will contain the corresponding element's value. For example: false is accessible via ${settings.offline}.
Java System Properties: All properties accessible via java.lang.System.getProperties() a-re available as POM properties, such as ${java.home}.
x: Set within a element in the POM. The value of value may be used as ${someVar}.
What can i add also in properties tag ?
You can add all the variables which you need to reuse later in your maven pom file.
For e.g. Below POM snippet reuses jackson.version 4 times.
<properties> <jackson.version>2.10.2</jackson.version> <dropwizard.version>2.0.1</dropwizard.version> <websocket.version>1.4.0</websocket.version> <apachehttp.version>4.5.10</apachehttp.version>
</properties>
<dependencies> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>${apachehttp.version}</version> </dependency> <dependency> <groupId>org.java-websocket</groupId> <artifactId>Java-WebSocket</artifactId> <version>${websocket.version}</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>${jackson.version}</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-annotations</artifactId> <version>${jackson.version}</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>${jackson.version}</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.dataformat</groupId> <artifactId>jackson-dataformat-yaml</artifactId> <version>${jackson.version}</version> </dependency> <dependencies>References :
