Scala: Static methods in interface require -target:jvm-1.8

[Lu Weizheng]

Hi all,

I recently upgraded Intellij IEDA from 2019 to 2020.2 Community Edition. I 
didn’t do anything to Maven.
My code could compile correctly before. But now I get the following error:

Static methods in interface require -target:jvm-1.8

Probably because I use new WatermarkStrategy Scala API:

.assignTimestampsAndWatermarks(
  WatermarkStrategy
    .forBoundedOutOfOrderness(Duration.ofSeconds(1))
    .withTimestampAssigner(new SerializableTimestampAssigner[(String, Long, 
Int)] {
      override def extractTimestamp(t: (String, Long, Int), l: Long): Long = 
t._2
    })
)

My project have both java and scala code. Here’s my POM.xml file:

<!-- Scala Compiler -->
         <plugin>
            <groupId>net.alchim31.maven</groupId>
            <artifactId>scala-maven-plugin</artifactId>
<!--            <version>3.2.2</version>-->
            <executions>
               <execution>
                  <id>scala-compile-first</id>
                  <phase>process-resources</phase>
                  <goals>
                     <goal>compile</goal>
                  </goals>
               </execution>
            </executions>
<!--            <executions>-->
<!--               <execution>-->
<!--                  <goals>-->
<!--                     <goal>compile</goal>-->
<!--                     <goal>testCompile</goal>-->
<!--                  </goals>-->
<!--               </execution>-->
<!--            </executions>-->
         </plugin>

Is there something I need to add to my POM file?




Best Regards,
Weizheng Lu