In Neo4j 5.x or 4.4.x, after we install the graph database plugin, we can observe some WARN messages in Neo4j server debug.log during the bootstrap phase, such as "Failed to load from plugin jar".

GDS : neo4j-graph-data-science-2.3.3.jar
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.codec.spdy.SpdyHeaderBlockJZlibEncoder` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: Lcom/neo4j/gds/shaded/com/jcraft/jzlib/Deflater;
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.JettyNpnSslEngine` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/eclipse/jetty/npn/NextProtoNego$Provider
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.JettyAlpnSslEngine$ClientEngine` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/eclipse/jetty/alpn/ALPN$Provider
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.util.BouncyCastleSelfSignedCertGenerator` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/bouncycastle/cert/X509v3CertificateBuilder
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.ConscryptAlpnSslEngine$BufferAdapter` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/conscrypt/AllocatedBuffer
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.ConscryptAlpnSslEngine$ClientEngine` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/conscrypt/BufferAllocator
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.JettyAlpnSslEngine$ClientEngine$1` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/eclipse/jetty/alpn/ALPN$ClientProvider
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.JettyAlpnSslEngine$ServerEngine` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/eclipse/jetty/alpn/ALPN$Provider
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.ConscryptAlpnSslEngine` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/conscrypt/BufferAllocator
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.JettyAlpnSslEngine$ServerEngine$1` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/eclipse/jetty/alpn/ALPN$ServerProvider
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.JettyNpnSslEngine$1` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/eclipse/jetty/npn/NextProtoNego$ServerProvider
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.ConscryptAlpnSslEngine$ServerEngine$1` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/conscrypt/HandshakeListener
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.ConscryptAlpnSslEngine$BufferAllocatorAdapter` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/conscrypt/BufferAllocator
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.JettyNpnSslEngine$2` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/eclipse/jetty/npn/NextProtoNego$ClientProvider
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.ConscryptAlpnSslEngine$ServerEngine` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/conscrypt/BufferAllocator
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.ConscryptAlpnSslEngine$ClientEngine$1` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/conscrypt/HandshakeListener
 WARN [o.n.k.a.p.GlobalProcedures] Failed to load `com.neo4j.gds.shaded.io.netty.handler.ssl.BouncyCastlePemReader` from plugin jar `/home/graphuser/neo4j/plugins/neo4j-graph-data-science-2.3.3.jar`: java.lang.NoClassDefFoundError: com/neo4j/gds/shaded/org/bouncycastle/openssl/PEMParser

 We could also see these messages within debug.log, as follows:

[o.n.g.c.GdsProxyExtension] GDS compatibility: for Neo4j Settings 4.4 -- available, for Neo4j Settings 5.1 (placeholder) -- not available, for Neo4j Settings 5.2.0 (placeholder) -- not available, for Neo4j Settings 5.3 (placeholder) -- not available, for Neo4j Settings 5.4 (placeholder) -- not available, for Neo4j Settings 5.5 (placeholder) -- not available, for Neo4j Settings 5.6 (placeholder) -- not available, for Neo4j Settings 5.7 (placeholder) -- not available, for Neo4j Settings 5.8 (placeholder) -- not available, selected: Neo4j Settings 4.4
[o.n.g.c.GdsProxyExtension] GDS compatibility: for Neo4j 4.4 -- available, for Neo4j 5.1 (placeholder) -- not available, for Neo4j 5.2.0 (placeholder) -- not available, for Neo4j 5.3 (placeholder) -- not available, for Neo4j 5.4 (placeholder) -- not available, for Neo4j 5.5 (placeholder) -- not available, for Neo4j 5.6 (placeholder) -- not available, for Neo4j 5.7 (placeholder) -- not available, for Neo4j 5.8 (placeholder) -- not available, selected: Neo4j 4.4

These are just informational messages and are not blocking the server from starting nor affect GDS functioning.
The reason for having these messages is because GDS supports multiple Neo4j versions at the same time and loads different classes depending on the Neo4j version. Currently in Neo4j server, these messages are not silenced in debug.log.
 

These messages are expected and have no effect on stability, and are no reason for concern. 
 

Compatibility matrix 

The link below maintains the up-to-date version compatibility if beyond those listed above:
https://neo4j.com/docs/graph-data-science/current/installation/supported-neo4j-versions/
 

To verify Neo4j GDS installation, print the version of Graph Data Science by executing the following Cypher query:

RETURN gds.version();

CALL gds.list();