.travis.yml

 language: java
 
 jdk:
+  - oraclejdk9
   - oraclejdk8
 
 install: true

debian/changelog

-libexternalsortinginjava-java (0.2.4-1) UNRELEASED; urgency=medium
+libexternalsortinginjava-java (0.2.5-1) unstable; urgency=medium
 
   * New upstream version
-  * Standards-Version: 4.1.4
   * Point Vcs-fields to Salsa
-  * debhelper 11
-  TODO: build fails
-   [ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:3.0.0:jar (default-cli) on project externalsortinginjava: Execution default-cli of goal org.apache.maven.plugins:maven-javadoc-plugin:3.0.0:jar failed.: NullPointerException -> [Help 1]
-   [ERROR] 
-   [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
-   [ERROR] Re-run Maven using the -X switch to enable full debug logging.
+  * debhelper 12
+  * Standards-Version: 4.3.0
+  * Secure URI in copyright format
+  * Drop useless get-orig-source target
+  * Remove trailing whitespace in debian/changelog
 
- -- Andreas Tille <tille@debian.org>  Wed, 02 May 2018 08:03:42 +0200
+ -- Andreas Tille <tille@debian.org>  Sat, 12 Jan 2019 09:11:55 +0100
 
 libexternalsortinginjava-java (0.2.3-1) unstable; urgency=medium
 

debian/compat

-11
+12

debian/control

@@ -3,14 +3,14 @@ Maintainer: Debian Java Maintainers <pkg-java-maintainers@lists.alioth.debian.or
 Uploaders: Andreas Tille <tille@debian.org>
 Section: java
 Priority: optional
-Build-Depends: debhelper (>= 11~),
+Build-Depends: debhelper (>= 12~),
                default-jdk,
                maven-debian-helper (>= 2.1)
 Build-Depends-Indep: libmaven-dependency-plugin-java,
                      junit4,
                      default-jdk-doc,
                      libmaven-javadoc-plugin-java
-Standards-Version: 4.1.4
+Standards-Version: 4.3.0
 Vcs-Browser: https://salsa.debian.org/java-team/libexternalsortinginjava-java
 Vcs-Git: https://salsa.debian.org/java-team/libexternalsortinginjava-java.git
 HHomepage: http://github.com/lemire/externalsortinginjava/

debian/copyright

-Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
 Upstream-Name: externalsortinginjava
 Source: http://github.com/lemire/externalsortinginjava/
 

debian/rules

@@ -3,5 +3,3 @@
 %:
 	dh $@
 
-get-orig-source:
-	uscan --download-current-version --force-download --no-symlink

pom.xml

@@ -3,7 +3,7 @@
     <groupId>com.google.code.externalsortinginjava</groupId>
     <artifactId>externalsortinginjava</artifactId>
     <packaging>jar</packaging>
-    <version>0.2.4</version>
+    <version>0.2.5</version>
     <name>externalsortinginjava</name>
     <url>http://github.com/lemire/externalsortinginjava/</url>
     <description>Sometimes, you want to sort large file without first loading them into memory. The solution is to use External Sorting. You divide the files into small blocks, sort each block in RAM, and then merge the result.
@@ -198,6 +198,6 @@
         <connection>scm:git:git@github.com:lemire/externalsortinginjava.git</connection>
         <url>scm:git:git@github.com:lemire/externalsortinginjava.git</url>
         <developerConnection>scm:git:git@github.com:lemire/externalsortinginjava.git</developerConnection>
-        <tag>externalsortinginjava-0.2.4</tag>
+        <tag>externalsortinginjava-0.2.5</tag>
     </scm>
 </project>

src/main/java/com/google/code/externalsorting/ExternalSort.java

@@ -434,6 +434,23 @@ public class ExternalSort {
                         output);
         }
 
+        /**
+         * This sorts a file (input) to an output file (output) using customized comparator
+         *
+         * @param input source file
+         *
+         * @param output output file
+         *
+         * @param cmp The {@link Comparator} to use to compare
+         *                {@link String}s.
+         * @throws IOException generic IO exception
+         */
+        public static void sort(final File input, final File output, final Comparator<String> cmp)
+                throws IOException {
+                ExternalSort.mergeSortedFiles(ExternalSort.sortInBatch(input),
+                        output, cmp);
+        }
+
         /**
          * Sort a list and save it to a temporary file
          *