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

Posted 2023-04-18

【中文标题】！ java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;

【英文标题】：! java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;

【发布时间】：2016-05-18 17:21:43

【问题描述】：

我在使用 neo4j-2.3.3 版本时遇到了上述错误。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>

它找不到类的任何原因？我检查了有效的依赖关系，发现如下

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

正如这篇文章中提到的https://groups.google.com/forum/#!topic/neo4j/l3HPGme7ND0

【问题讨论】：

你是否像谷歌群组问题所说的那样添加了 scala 2.11.7 作为依赖项？

是的，我将其添加为显式依赖项

【参考方案1】：

问题似乎是 scala 版本控制问题：可能其中一个类与 2.11.7 不兼容。我查看了akka 库，看起来还可以。

 Akka 2.3.11 is released for Scala 2.10.4 and 2.11.5

但这是一个主要/可能的罪魁祸首：

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

2.10 显然不会与 2.11.X 一起飞行。

【讨论】：

@user_mda OK 更新了我的答案：看看你有一个不兼容的 akka 版本依赖。

@user_mda 您是否尝试过我上面的评论 - 删除或更新 akka-actor_2.10 依赖项？

我将 akka 版本降级到 2.3.9，但还是一样

@user_mda akka 版本已经太旧了 - 你想要一个与 scala 2.11 兼容的新版本

@user_mda 。你有没有想过删除旧版本的 akka 2.10 ？？