I am new to Maven. I do not know anything about it. I download an open source maven project form Github. I open it in Eclipse. I modified only one line to modified the pattern for date from this format:
final String pattern = "%d{yyyy-MM-dd HH:mm:ss} %-5p - %m%n";
To this
final String pattern = "%d{yyyy-MM-dd HH:mm:ss:SSS} %-5p - %m%n";
Then, I tried to produce the jar file for the project. The pom.xml that come with the downloaded project is using package shade plugin.
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>${shade.version}</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<finalName>name-of-pro-${project.version}</finalName>
<transformers>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>name.of.the.package.and.Mainclass</mainClass>
</transformer>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer" />
</transformers>
<filters>
<!-- This is necessary to avoid a java.lang.SecurityException -->
<filter>
<artifact>*:*</artifact>
<excludes>
<exclude>META-INF/*.SF</exclude>
<exclude>META-INF/*.DSA</exclude>
<exclude>META-INF/*.RSA</exclude>
</excludes>
</filter>
</filters>
</configuration>
</execution>
</executions>
</plugin>
So, I tried to get jar file from maven using this command:
mvn clean package
However, when I run the produced jar file using this command:
java -jar app-0.2.0-SNAPSHOT.jar
I got the (no main manifest attribute) error.
no main manifest attribute, in app-0.2.0-SNAPSHOT.jar
I searched for the MANIFEST.MF file to check for the attributes there, but I cloud not find it.
Cloud anyone help me if I missing some setting?
You cannot just run a jar.
Either you need to specify the full classpath on the command line or you need to build the jar as jar-with-dependencies as e.g. described here: