try to get more memory from Travis

.travis.yml

@@ -47,6 +47,7 @@ addons:
 before_install:
   - source dmlc-core/scripts/travis/travis_setup_env.sh
   - export PYTHONPATH=${PYTHONPATH}:${PWD}/python-package
+  - echo "MAVEN_OPTS='-Xmx2048m -XX:MaxPermSize=1024m -XX:ReservedCodeCacheSize=512m'" > ~/.mavenrc 
 
 install:
   - source tests/travis/setup.sh

jvm-packages/pom.xml

@@ -101,6 +101,7 @@
                     <descriptorRefs>
                         <descriptorRef>jar-with-dependencies</descriptorRef>
                     </descriptorRefs>
+                    <skipAssembly>true</skipAssembly>
                 </configuration>
                 <executions>
                     <execution>

jvm-packages/xgboost4j-demo/pom.xml

@@ -11,6 +11,17 @@
     <artifactId>xgboost4j-demo</artifactId>
     <version>0.1</version>
     <packaging>jar</packaging>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <configuration>
+                    <skipAssembly>false</skipAssembly>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
     <dependencies>
         <dependency>
             <groupId>ml.dmlc</groupId>

jvm-packages/xgboost4j-spark/pom.xml

@@ -9,6 +9,17 @@
         <version>0.1</version>
     </parent>
     <artifactId>xgboost4jspark</artifactId>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <configuration>
+                    <skipAssembly>false</skipAssembly>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
     <dependencies>
         <dependency>
             <groupId>ml.dmlc</groupId>

jvm-packages/xgboost4j/pom.xml

@@ -22,6 +22,13 @@
                     <nohelp>true</nohelp>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <configuration>
+                    <skipAssembly>false</skipAssembly>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.scalatest</groupId>
                 <artifactId>scalatest-maven-plugin</artifactId>