Question

I'm tying to create an Maven index for my private project and I'm tying to use org.apache.maven.indexer:indexer-cli:7.1.1 to do so. However, when calling the jar all I get is an error message:

>  java -jar /…/org/apache/maven/indexer/indexer-cli/7.1.1/indexer-cli-7.1.1.jar  \ 
        --repository    "${HOMEPAGE_DEPLOY}"                                    \
        --index         "${HOMEPAGE_DEPLOY}/.index"                             \
        --destination   "${HOMEPAGE_DEPLOY}/.index"                             \
        --name          "${PROJECT_NAME}"
kein Hauptmanifestattribut, in /…/org/apache/maven/indexer/indexer-cli/7.1.1/indexer-cli-7.1.1.jar

Yes, all pathnames have been checked and a simplified call doesn't work as well:

>pushd /…/org/apache/maven/indexer/indexer-cli/7.1.1/
>java -jar indexer-cli-7.1.1.jar 
kein Hauptmanifestattribut, in indexer-cli-7.1.1.jar

The only documentation I found uses java -jar as well but that was for version 5.1.1 so I wonder if something changed.

I know about the nexus indexer but that one has stopped working after I moved to Java 11 and I don't want to be stuck with Java 8 forever. (They should have called Java 9 Java 2.0 as it's a mayor and incompatible upgrade)

Update 1:

For completeness sake I did try org.apache.maven.indexer:indexer-cli:5.1.1 and that actually works as expected. As does org.apache.maven.indexer:indexer-cli:6.2.2 but not org.apache.maven.indexer:indexer-cli:7.0.4.

So it's change for Version 7.

Update 2:

After @khmarbaise question I decided to check the content of the the Jar-file. The file content looks ok and a MANIFEST.MF is present.

>7z l /…/org/apache/maven/indexer/indexer-cli/7.1.1/indexer-cli-7.1.1.jar

7-Zip [64] 17.05 : Copyright (c) 1999-2021 Igor Pavlov : 2017-08-28
p7zip Version 17.05 (locale=utf8,Utf16=on,HugeFiles=on,64 bits,16 CPUs x64)

Scanning the drive for archives:
1 file, 22886 bytes (23 KiB)                                                

Listing archive: /…/org/apache/maven/indexer/indexer-cli/7.1.1/indexer-cli-7.1.1.jar

--
Path = /…/org/apache/maven/indexer/indexer-cli/7.1.1/indexer-cli-7.1.1.jar
Type = zip
Physical Size = 22886

   Date      Time    Attr         Size   Compressed  Name
------------------- ----- ------------ ------------  ------------------------
2023-12-13 22:35:30 D....            0            0  META-INF
2023-12-13 22:35:30 .....          336          171  META-INF/MANIFEST.MF
2023-12-13 22:35:30 D....            0            0  META-INF/sisu
2023-12-13 22:35:30 D....            0            0  org
2023-12-13 22:35:30 D....            0            0  org/apache
2023-12-13 22:35:30 D....            0            0  org/apache/maven
2023-12-13 22:35:30 D....            0            0  org/apache/maven/index
2023-12-13 22:35:30 D....            0            0  org/apache/maven/index/cli
2023-12-13 22:35:30 D....            0            0  META-INF/maven
2023-12-13 22:35:30 D....            0            0  META-INF/maven/org.apache.maven.indexer
2023-12-13 22:35:30 D....            0            0  META-INF/maven/org.apache.maven.indexer/indexer-cli
2023-12-13 22:35:30 .....         6190         1331  META-INF/DEPENDENCIES
2023-12-13 22:35:30 .....        11358         3949  META-INF/LICENSE
2023-12-13 22:35:30 .....          175          130  META-INF/NOTICE
2023-12-13 22:35:30 .....           38           40  META-INF/sisu/javax.inject.Named
2023-12-13 22:35:30 .....          732          403  org/apache/maven/index/cli/Components.class
2023-12-13 22:35:30 .....         1016          516  org/apache/maven/index/cli/NexusIndexerCli$1.class
2023-12-13 22:35:30 .....         4316         2051  org/apache/maven/index/cli/NexusIndexerCli$IndexerListener.class
2023-12-13 22:35:30 .....        17445         8267  org/apache/maven/index/cli/NexusIndexerCli.class
2023-12-13 22:35:30 .....         2093          951  org/apache/maven/index/cli/PartialImplementation.class
2023-12-13 22:35:30 .....         6685         1917  META-INF/maven/org.apache.maven.indexer/indexer-cli/pom.xml
2023-12-13 22:35:30 .....           70           66  META-INF/maven/org.apache.maven.indexer/indexer-cli/pom.properties
------------------- ----- ------------ ------------  ------------------------
2023-12-13 22:35:30              50454        19792  12 files, 10 folders

I checked the sha1 checksum as well and is matches as well. Lastly I checked the MANIFEST.MF which is indeed missing the the Main-Class: entry:

>cat META-INF/MANIFEST.MF 
Manifest-Version: 1.0
Created-By: Maven JAR Plugin 3.3.0
Build-Jdk-Spec: 21
Specification-Title: Maven :: Indexer CLI
Specification-Version: 7.1
Specification-Vendor: The Apache Software Foundation
Implementation-Title: Maven :: Indexer CLI
Implementation-Version: 7.1.1
Implementation-Vendor: The Apache Software Foundation

Why did it work for @khmarbaise with a missing Main-Class: in the MANIFEST.MF?

Update 3:

Installed java 21 and tried again. Same result for Oracle Java and openjdk:

>JDK_HOME=/Library/Java/JavaVirtualMachines/jdk-21.jdk/Contents/Home \
>JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-21.jdk/Contents/Home \
>/Library/Java/JavaVirtualMachines/jdk-21.jdk/Contents/Home/bin/java -jar indexer-cli-7.1.1.jar
kein Hauptmanifestattribut, in indexer-cli-7.1.1.jar

>JDK_HOME=/usr/local/Cellar/openjdk/21.0.1/libexec/openjdk.jdk/Contents/Home \
>JAVA_HOME=/usr/local/Cellar/openjdk/21.0.1/libexec/openjdk.jdk/Contents/Home \
>/usr/local/Cellar/openjdk/21.0.1/libexec/openjdk.jdk/Contents/Home/bin/java -jar indexer-cli-7.1.1.jar
kein Hauptmanifestattribut, in indexer-cli-7.1.1.jar

Answer

Answering my own question (again). With Version 7 and onwards the file structure of indexer-cli package has changed. For comparison:

Version 6.2.2:

org/apache/maven/indexer/indexer-cli/6.2.2
../
indexer-cli-6.2.2-javadoc.jar                     2022-07-16 15:47    136897      
indexer-cli-6.2.2-javadoc.jar.asc                 2022-07-16 15:47       833      
indexer-cli-6.2.2-javadoc.jar.md5                 2022-07-16 15:47        32      
indexer-cli-6.2.2-javadoc.jar.sha1                2022-07-16 15:47        40      
indexer-cli-6.2.2-sources.jar                     2022-07-16 15:47     15752      
indexer-cli-6.2.2-sources.jar.asc                 2022-07-16 15:47       833      
indexer-cli-6.2.2-sources.jar.md5                 2022-07-16 15:47        32      
indexer-cli-6.2.2-sources.jar.sha1                2022-07-16 15:47        40      
indexer-cli-6.2.2.jar                             2022-07-16 15:47  12672807      
indexer-cli-6.2.2.jar.asc                         2022-07-16 15:47       833      
indexer-cli-6.2.2.jar.md5                         2022-07-16 15:47        32      
indexer-cli-6.2.2.jar.sha1                        2022-07-16 15:47        40      
indexer-cli-6.2.2.pom                             2022-07-16 15:47      6599      
indexer-cli-6.2.2.pom.asc                         2022-07-16 15:47       833      
indexer-cli-6.2.2.pom.md5                         2022-07-16 15:47        32      
indexer-cli-6.2.2.pom.sha1                        2022-07-16 15:47        40      

Version 7.1.1:

org/apache/maven/indexer/indexer-cli/7.1.1
../
indexer-cli-7.1.1-cli.jar                         2023-12-13 22:39  13617488      
indexer-cli-7.1.1-cli.jar.asc                     2023-12-13 22:39       833      
indexer-cli-7.1.1-cli.jar.md5                     2023-12-13 22:39        32      
indexer-cli-7.1.1-cli.jar.sha1                    2023-12-13 22:39        40      
indexer-cli-7.1.1-cyclonedx.json                  2023-12-13 22:39     78614      
indexer-cli-7.1.1-cyclonedx.json.asc              2023-12-13 22:39       833      
indexer-cli-7.1.1-cyclonedx.json.md5              2023-12-13 22:39        32      
indexer-cli-7.1.1-cyclonedx.json.sha1             2023-12-13 22:39        40      
indexer-cli-7.1.1-cyclonedx.xml                   2023-12-13 22:39     66952      
indexer-cli-7.1.1-cyclonedx.xml.asc               2023-12-13 22:39       833      
indexer-cli-7.1.1-cyclonedx.xml.md5               2023-12-13 22:39        32      
indexer-cli-7.1.1-cyclonedx.xml.sha1              2023-12-13 22:39        40      
indexer-cli-7.1.1-javadoc.jar                     2023-12-13 22:39    114999      
indexer-cli-7.1.1-javadoc.jar.asc                 2023-12-13 22:39       833      
indexer-cli-7.1.1-javadoc.jar.md5                 2023-12-13 22:39        32      
indexer-cli-7.1.1-javadoc.jar.sha1                2023-12-13 22:39        40      
indexer-cli-7.1.1-sources.jar                     2023-12-13 22:39     17046      
indexer-cli-7.1.1-sources.jar.asc                 2023-12-13 22:39       833      
indexer-cli-7.1.1-sources.jar.md5                 2023-12-13 22:39        32      
indexer-cli-7.1.1-sources.jar.sha1                2023-12-13 22:39        40      
indexer-cli-7.1.1.jar                             2023-12-13 22:39     22886      
indexer-cli-7.1.1.jar.asc                         2023-12-13 22:39       833      
indexer-cli-7.1.1.jar.md5                         2023-12-13 22:39        32      
indexer-cli-7.1.1.jar.sha1                        2023-12-13 22:39        40      
indexer-cli-7.1.1.pom                             2023-12-13 22:39      6685      
indexer-cli-7.1.1.pom.asc                         2023-12-13 22:39       833      
indexer-cli-7.1.1.pom.md5                         2023-12-13 22:39        32      
indexer-cli-7.1.1.pom.sha1                        2023-12-13 22:39        40      

There are now far more files then before and the name of the actual executable has changed from indexer-cli-6.2.2.jar to indexer-cli-7.1.1-cli.jar