! java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;

Question

我在使用 neo4j-2.3.3 版本时运行出现了上述错误。这是 pom 文件

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <dropwizard.version>0.8.1</dropwizard.version>
    <akka.version>2.3.11</akka.version>
    <aether.version>1.0.2.v20150114</aether.version>
    <neo4j.version>2.3.3</neo4j.version>
    <maven.version>3.3.1</maven.version>
    <cd_phase>deploy</cd_phase>
    <neo4j.ogm.version>2.0.1</neo4j.ogm.version>
</properties>

<repositories>
    <repository>
        <id>mvn-neo4j</id>
        <url>http://m2.neo4j.org/content/groups/everything</url>
    </repository>
</repositories>

<dependencies>

    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j</artifactId>
        <version>${neo4j.version}</version>

    </dependency>

    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-kernel</artifactId>
        <version>${neo4j.version}</version>
        <type>test-jar</type>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-io</artifactId>
        <version>${neo4j.version}</version>
        <type>test-jar</type>
        <scope>test</scope>
    </dependency>



    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-ogm-api</artifactId>
        <version>${neo4j.ogm.version}</version>
    </dependency>
    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-ogm-core</artifactId>
        <version>${neo4j.ogm.version}</version>
    </dependency>


    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>


    <dependency>
        <groupId>io.dropwizard</groupId>
        <artifactId>dropwizard-core</artifactId>
        <version>${dropwizard.version}</version>
    </dependency>

    <dependency>
        <groupId>io.dropwizard.metrics</groupId>
        <artifactId>metrics-graphite</artifactId>
        <version>3.1.1</version>
    </dependency>

    <dependency>
        <groupId>io.dropwizard</groupId>
        <artifactId>dropwizard-testing</artifactId>
        <version>${dropwizard.version}</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j</artifactId>
        <version>${neo4j.version}</version>
    </dependency>

    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-kernel</artifactId>
        <version>${neo4j.version}</version>
        <type>test-jar</type>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j-io</artifactId>
        <version>${neo4j.version}</version>
        <type>test-jar</type>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>com.tinkerpop.blueprints</groupId>
        <artifactId>blueprints-neo4j2-graph</artifactId>
        <version>2.6.0</version>
        <exclusions>
            <exclusion>
                <groupId>org.neo4j</groupId>
                <artifactId>neo4j</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.neo4j</groupId>
                <artifactId>neo4j-kernel</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.neo4j</groupId>
                <artifactId>neo4j-io</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.neo4j</groupId>
                <artifactId>neo4j-ha</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.neo4j</groupId>
                <artifactId>neo4j-management</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>com.typesafe.akka</groupId>
        <artifactId>akka-actor_2.10</artifactId>
        <version>${akka.version}</version>
    </dependency>

    <dependency>
        <groupId>com.typesafe.akka</groupId>
        <artifactId>akka-slf4j_2.10</artifactId>
        <version>${akka.version}</version>
    </dependency>

    <dependency>
        <groupId>org.scala-lang</groupId>
        <artifactId>scala-compiler</artifactId>
        <version>2.11.7</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.typesafe.akka</groupId>
        <artifactId>akka-testkit_2.10</artifactId>
        <version>${akka.version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jersey.core</groupId>
        <artifactId>jersey-client</artifactId>
        <version>2.17</version>
    </dependency>

    <dependency>
        <groupId>org.hamcrest</groupId>
        <artifactId>hamcrest-library</artifactId>
        <version>1.3</version>
    </dependency>
</dependencies>

为什么找不到 class？我检查了有效的依赖项，发现了以下

 <dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-compiler</artifactId>
      <version>2.11.7</version>
      <scope>test</scope>
    </dependency>

如本文所述posthttps://groups.google.com/forum/#!topic/neo4j/l3HPGme7ND0

Answer 1

问题似乎是 Scala 版本控制问题：可能类之一与 2.11.7 不兼容。我查看了 akka 库，似乎还可以。

 Akka 2.3.11 is released for Scala 2.10.4 and 2.11.5

但这里有一个 prime/likely 罪魁祸首：

<dependency>
    <groupId>com.typesafe.akka</groupId>
    <artifactId>akka-actor_2.10</artifactId>
    <version>${akka.version}</version>
</dependency>

2.10 显然不会用 2.11.X.

! java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;

! java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;

scala

noclassdeffounderror

neo4j

maven