Bring Python current in Travis

.travis.yml

@@ -1,24 +1,30 @@
 language: python
-jdk: openjdk8
-dist: xenial
+dist: bionic
+addons:
+  apt:
+    packages:
+    - openjdk-8-jdk
 cache:
   pip: true
 python:
   - "3.5"
   - "3.6"
   - "3.7"
+  - "3.8"
+  - "3.9"
 before_install:
   - mkdir -p /opt
-  - wget -q -O /opt/spark.tgz https://archive.apache.org/dist/spark/spark-2.4.3/spark-2.4.3-bin-hadoop2.7.tgz
+  - wget -q -O /opt/spark.tgz https://archive.apache.org/dist/spark/spark-2.4.7/spark-2.4.7-bin-hadoop2.7.tgz
   - tar xzf /opt/spark.tgz -C /opt/
   - rm /opt/spark.tgz
-  - export SPARK_HOME=/opt/spark-2.4.3-bin-hadoop2.7
-  - export PATH=$PATH:/opt/spark-2.4.3-bin-hadoop2.7/bin
-  - export PATH=$(echo "$PATH" | sed -e 's/:\/usr\/local\/lib\/jvm\/openjdk11\/bin//')
-  - export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64
-install:
+  - export SPARK_HOME=/opt/spark-2.4.7-bin-hadoop2.7
+  - export PATH=$PATH:/opt/spark-2.4.7-bin-hadoop2.7/bin
+  - ls -l /usr/lib/jvm
+  - export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
+  - export PATH=$JAVA_HOME/bin:$PATH
+  - java -version
   - pip install -r test-requirements.txt
-  - pip install pyspark==2.4.3
+  - pip install pyspark==2.4.7
   - pip install pytest-spark==0.4.5
 script:
   - python -m pytest