jOOQ code generation Keys.java member ordering - code-generation

Question

For the given jOOQ Maven code generation:
<profile>
<id>code-generation</id>
<build>
<plugins>
<plugin>
<groupId>org.jooq</groupId>
<artifactId>jooq-codegen-maven</artifactId>
<version>${jooq.version}</version>
<executions>
<execution>
<goals>
<goal>generate</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>9.4-1200-jdbc41</version>
</dependency>
</dependencies>
<configuration>
<jdbc>
<driver>org.postgresql.Driver</driver>
<url>${postgres.connection_string}</url>
<user>${postgres.user}</user>
<password></password>
</jdbc>
<generator>
<name>org.jooq.util.JavaGenerator</name>
<database>
<name>org.jooq.util.postgres.PostgresDatabase</name>
<includes>.*</includes>
<excludes></excludes>
<inputSchema>public</inputSchema>
</database>
<target>
<packageName>${packagename_123}</packageName>
<directory>src/main/java/</directory>
</target>
</generator>
</configuration>
</plugin>
</plugins>
</build>
</profile>
The generated Keys.java generates the following on my local developer machine:
public static final UniqueKey<BillItemRecord> BILL_ITEM_PKEY = UniqueKeys0.BILL_ITEM_PKEY;
public static final UniqueKey<BillingHistoryRecord> BILLING_HISTORY_PKEY = UniqueKeys0.BILLING_HISTORY_PKEY;
On my CI machine the same Keys.java file has sorted the two lines in the opposite order:
public static final UniqueKey<BillingHistoryRecord> BILLING_HISTORY_PKEY = UniqueKeys0.BILLING_HISTORY_PKEY;
public static final UniqueKey<BillItemRecord> BILL_ITEM_PKEY = UniqueKeys0.BILL_ITEM_PKEY;
Why are these two lines being sorted differently?