|
| 1 | +# Troubleshooting |
| 2 | + |
| 3 | +## "ALPN is not configured properly" |
| 4 | + |
| 5 | +This exception usually indicates that Netty isn't set up properly. |
| 6 | + |
| 7 | +If using gRPC version 1.9.0 or newer, consider using `io.grpc:grpc-netty-shaded` |
| 8 | +dependency so that it does not conflict with other packages that also require Netty. |
| 9 | + |
| 10 | +If your gRPC dependency is older than 1.9.0, consider updating. |
| 11 | +As of 0.35.0, packages in `google-cloud-java` already declare a dependency on `grpc-netty-shaded`. |
| 12 | + |
| 13 | +The versions of `gprc-netty-shaded` must match the version of other gRPC dependencies. |
| 14 | +Packages in `google-cloud-java` already do this for you. |
| 15 | +However, if you need to declare dependency on gRPC yourself, we recommend doing it like this: |
| 16 | +``` |
| 17 | +<properties> |
| 18 | + <grpc.version>1.9.0</grpc.version> |
| 19 | +</properties> |
| 20 | +
|
| 21 | +<dependencyManagement> |
| 22 | + <dependencies> |
| 23 | + <dependency> |
| 24 | + <groupId>io.grpc</groupId> |
| 25 | + <artifactId>grpc-core</artifactId> |
| 26 | + <version>${grpc.version}</version> |
| 27 | + </dependency> |
| 28 | + <dependency> |
| 29 | + <groupId>io.grpc</groupId> |
| 30 | + <artifactId>grpc-netty-shaded</artifactId> |
| 31 | + <version>${grpc.version}</version> |
| 32 | + </dependency> |
| 33 | + </dependencies> |
| 34 | +</dependencyManagement> |
| 35 | +``` |
| 36 | +so that versions cannot go out of sync. |
| 37 | + |
| 38 | +See [gRPC documentation](https://github.com/grpc/grpc-java/blob/master/SECURITY.md#troubleshooting) |
| 39 | +for more details. |
| 40 | + |
| 41 | +## `ClassNotFoundException` or `NoSuchMethodError` |
| 42 | + |
| 43 | +This is usually caused by multiple packages depending on different versions |
| 44 | +of the same dependencies. |
| 45 | +`com.google.protobuf:protobuf-java` and `com.google.guava:guava` are the usual culprits, |
| 46 | +since they are widely used. |
| 47 | + |
| 48 | +Consider using the [Enforcer Plugin](https://maven.apache.org/enforcer/maven-enforcer-plugin/index.html) |
| 49 | +to verify version convergence. |
| 50 | + |
| 51 | +Alternatively, consider [shading](https://maven.apache.org/plugins/maven-shade-plugin/) |
| 52 | +these dependencies. |
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