diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..7a57675
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,14 @@
+# https://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+
+[*.{java,py}]
+indent_style = space
+indent_size = 4
+
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..26113f5
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,15 @@
+# Normalize text to LF in the repository and working tree.
+* text=auto eol=lf
+
+# Windows command scripts (for example a future Maven wrapper) need CRLF.
+*.cmd text eol=crlf
+*.bat text eol=crlf
+
+# Binary files: never convert or diff as text.
+*.jar binary
+*.class binary
+*.jpg binary
+*.jpeg binary
+*.png binary
+*.gif binary
+*.ico binary
diff --git a/.gitignore b/.gitignore
index adc5f64..110f9aa 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
-*/target/**
-/target/**
+# Maven build output in every module
+target/
 # Intellij project files
 *.iml
 *.ipr
@@ -15,12 +15,6 @@ maven-eclipse.xml
 nb-configuration.xml
 */nbproject/*
 
-/jsp/target/
-/esapi/target/
-/target/
-/jakarta/target/
-/jakarta-test/target/
-
 # Python CI/compatibility tooling
 __pycache__/
 *.pyc
diff --git a/META-INF/MANIFEST.MF b/META-INF/MANIFEST.MF
deleted file mode 100644
index 2aaee67..0000000
--- a/META-INF/MANIFEST.MF
+++ /dev/null
@@ -1,9 +0,0 @@
-Manifest-Version: 1.0
-Bnd-LastModified: 1533328833261
-Bundle-ManifestVersion: 2
-Bundle-Name: org.owasp.encoder
-Bundle-SymbolicName: org.owasp.encoder
-Bundle-Version: 1.2.1
-Created-By: 1.8.0_181 (Oracle Corporation)
-Export-Package: org.owasp.encoder
-Tool: Bnd-1.50.0
diff --git a/compatibility/consumers.py b/compatibility/consumers.py
index 1bc5752..28b537a 100644
--- a/compatibility/consumers.py
+++ b/compatibility/consumers.py
@@ -147,6 +147,18 @@ def metadata(kind, jar, core):
     print('Metadata passed:', jar.name)
 
 
+def check_sources_jar(kind, jar):
+    """The published sources JAR must carry the Java 9 module descriptor source."""
+    source_jar = ROOT / kind / 'target' / (jar.name[:-len('.jar')] + '-sources.jar')
+    with zipfile.ZipFile(source_jar) as archive:
+        names = archive.namelist()
+    assert 'module-info.java' in names, (source_jar, 'missing module-info.java')
+    assert not any(name.endswith('.class') for name in names), source_jar
+    package = ARTIFACTS[kind][3].replace('.', '/') + '/'
+    assert any(name.startswith(package) and name.endswith('.java') for name in names), source_jar
+    print('Sources passed:', source_jar.name)
+
+
 def prepare(args):
     out = args.directory.resolve()
     if out.exists() and any(out.iterdir()):
@@ -167,6 +179,7 @@ def prepare(args):
         shutil.copy2(candidates[0], target)
         jars[kind] = target
     for kind, jar in jars.items(): metadata(kind, jar, jars['core'])
+    for kind, jar in jars.items(): check_sources_jar(kind, jar)
     run('javac', '--release', '9', '-d', out / 'metadata', SOURCE / 'ModuleMetadata.java')
     run('java', '-cp', out / 'metadata', 'consumer.ModuleMetadata', *jars.values())
     # javac's module discovery does not honor the runtime multi-release property.
diff --git a/core/pom.xml b/core/pom.xml
index 7893375..520c4eb 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -1,132 +1,132 @@
-<?xml version="1.0" encoding="US-ASCII"?>
-<!--
-~ Copyright (c) 2015 OWASP.
-~ All rights reserved.
-~
-~ Redistribution and use in source and binary forms, with or without
-~ modification, are permitted provided that the following conditions
-~ are met:
-~
-~     * Redistributions of source code must retain the above
-~       copyright notice, this list of conditions and the following
-~       disclaimer.
-~
-~     * Redistributions in binary form must reproduce the above
-~       copyright notice, this list of conditions and the following
-~       disclaimer in the documentation and/or other materials
-~       provided with the distribution.
-~
-~     * Neither the name of the OWASP nor the names of its
-~       contributors may be used to endorse or promote products
-~       derived from this software without specific prior written
-~       permission.
-~
-~ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-~ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-~ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
-~ FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
-~ COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
-~ INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
-~ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-~ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-~ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
-~ STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-~ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
-~ OF THE POSSIBILITY OF SUCH DAMAGE.
--->
-
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-
-    <parent>
-        <groupId>org.owasp.encoder</groupId>
-        <artifactId>encoder-parent</artifactId>
-        <version>1.5.0-SNAPSHOT</version>
-    </parent>
-
-    <artifactId>encoder</artifactId>
-    <packaging>jar</packaging>
-
-    <name>Java Encoder</name>
-    <description>
-        The OWASP Encoders package is a collection of high-performance low-overhead
-        contextual encoders, that when utilized correctly, is an effective tool in
-        preventing Web Application security vulnerabilities such as Cross-Site
-        Scripting.
-    </description>
-
-    <properties>
-        <jigsaw.module.name>org.owasp.encoder</jigsaw.module.name>
-        <osgi.symbolic.name>org.owasp.encoder</osgi.symbolic.name>
-    </properties>
-
-    <dependencies>
-        <!-- Keep this test fixture on OSGi R6 to detect compatibility regressions. -->
-        <dependency>
-            <groupId>org.apache.felix</groupId>
-            <artifactId>org.apache.felix.framework</artifactId>
-            <version>5.6.12</version>
-            <scope>test</scope>
-        </dependency>
-        <!-- Independent JSON parser used to check Encode.forJson output. -->
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>2.22.3</version>
-            <scope>test</scope>
-        </dependency>
-        <!-- Parse the enclosing HTML independently of the JSON encoder. -->
-        <dependency>
-            <groupId>org.jsoup</groupId>
-            <artifactId>jsoup</artifactId>
-            <version>1.23.2</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <build>
-        <plugins>
-            <!-- Make the multi-release JAR available to downstream reactor modules before they compile their JPMS descriptors. -->
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-jar-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <id>reactor-jar</id>
-                        <phase>process-classes</phase>
-                        <goals>
-                            <goal>jar</goal>
-                        </goals>
-                    </execution>
-                    <!-- The main artifact is already created during process-classes. -->
-                    <execution>
-                        <id>default-jar</id>
-                        <phase>none</phase>
-                        <goals>
-                            <goal>jar</goal>
-                        </goals>
-                    </execution>
-                </executions>
-            </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-failsafe-plugin</artifactId>
-                <configuration>
-                    <systemPropertyVariables>
-                        <encoder.bundle>${project.build.directory}/${project.build.finalName}.jar</encoder.bundle>
-                    </systemPropertyVariables>
-                </configuration>
-                <executions>
-                    <execution>
-                        <id>osgi-compatibility</id>
-                        <goals>
-                            <goal>integration-test</goal>
-                            <goal>verify</goal>
-                        </goals>
-                    </execution>
-                </executions>
-            </plugin>
-        </plugins>
-    </build>
-</project>
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+~ Copyright (c) 2015 OWASP.
+~ All rights reserved.
+~
+~ Redistribution and use in source and binary forms, with or without
+~ modification, are permitted provided that the following conditions
+~ are met:
+~
+~     * Redistributions of source code must retain the above
+~       copyright notice, this list of conditions and the following
+~       disclaimer.
+~
+~     * Redistributions in binary form must reproduce the above
+~       copyright notice, this list of conditions and the following
+~       disclaimer in the documentation and/or other materials
+~       provided with the distribution.
+~
+~     * Neither the name of the OWASP nor the names of its
+~       contributors may be used to endorse or promote products
+~       derived from this software without specific prior written
+~       permission.
+~
+~ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+~ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+~ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+~ FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+~ COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+~ INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+~ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+~ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+~ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+~ STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+~ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+~ OF THE POSSIBILITY OF SUCH DAMAGE.
+-->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.owasp.encoder</groupId>
+        <artifactId>encoder-parent</artifactId>
+        <version>1.5.0-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>encoder</artifactId>
+    <packaging>jar</packaging>
+
+    <name>Java Encoder</name>
+    <description>
+        The OWASP Encoders package is a collection of high-performance low-overhead
+        contextual encoders, that when utilized correctly, is an effective tool in
+        preventing Web Application security vulnerabilities such as Cross-Site
+        Scripting.
+    </description>
+
+    <properties>
+        <jigsaw.module.name>org.owasp.encoder</jigsaw.module.name>
+        <osgi.symbolic.name>org.owasp.encoder</osgi.symbolic.name>
+    </properties>
+
+    <dependencies>
+        <!-- Keep this test fixture on OSGi R6 to detect compatibility regressions. -->
+        <dependency>
+            <groupId>org.apache.felix</groupId>
+            <artifactId>org.apache.felix.framework</artifactId>
+            <version>5.6.12</version>
+            <scope>test</scope>
+        </dependency>
+        <!-- Independent JSON parser used to check Encode.forJson output. -->
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.22.3</version>
+            <scope>test</scope>
+        </dependency>
+        <!-- Parse the enclosing HTML independently of the JSON encoder. -->
+        <dependency>
+            <groupId>org.jsoup</groupId>
+            <artifactId>jsoup</artifactId>
+            <version>1.23.2</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <!-- Make the multi-release JAR available to downstream reactor modules before they compile their JPMS descriptors. -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <id>reactor-jar</id>
+                        <phase>process-classes</phase>
+                        <goals>
+                            <goal>jar</goal>
+                        </goals>
+                    </execution>
+                    <!-- The main artifact is already created during process-classes. -->
+                    <execution>
+                        <id>default-jar</id>
+                        <phase>none</phase>
+                        <goals>
+                            <goal>jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-failsafe-plugin</artifactId>
+                <configuration>
+                    <systemPropertyVariables>
+                        <encoder.bundle>${project.build.directory}/${project.build.finalName}.jar</encoder.bundle>
+                    </systemPropertyVariables>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>osgi-compatibility</id>
+                        <goals>
+                            <goal>integration-test</goal>
+                            <goal>verify</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>
diff --git a/core/src/main/java/org/owasp/encoder/UnsupportedContextException.java b/core/src/main/java/org/owasp/encoder/UnsupportedContextException.java
index e904ee1..6850f0c 100644
--- a/core/src/main/java/org/owasp/encoder/UnsupportedContextException.java
+++ b/core/src/main/java/org/owasp/encoder/UnsupportedContextException.java
@@ -41,6 +41,12 @@
  * @author Jeff Ichnowski
  */
 public class UnsupportedContextException extends RuntimeException {
+    /**
+     * The value the JVM computed for every released version (1.2 through
+     * 1.4.0), declared explicitly so serialized instances stay compatible.
+     */
+    private static final long serialVersionUID = -1517019963198920181L;
+
     /**
      * Sole constructor.
      *
diff --git a/core/src/site/site.xml b/core/src/site/site.xml
index 1b3cb62..174eb2f 100644
--- a/core/src/site/site.xml
+++ b/core/src/site/site.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="ISO-8859-1"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
 Copyright (c) 2015 Jeremy Long
 All rights reserved.
diff --git a/core/src/test/java/org/owasp/encoder/UnsupportedContextExceptionTest.java b/core/src/test/java/org/owasp/encoder/UnsupportedContextExceptionTest.java
new file mode 100644
index 0000000..6b98f89
--- /dev/null
+++ b/core/src/test/java/org/owasp/encoder/UnsupportedContextExceptionTest.java
@@ -0,0 +1,64 @@
+// Copyright (c) 2026 OWASP
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+//
+//     * Redistributions of source code must retain the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer.
+//
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials
+//       provided with the distribution.
+//
+//     * Neither the name of the OWASP nor the names of its
+//       contributors may be used to endorse or promote products
+//       derived from this software without specific prior written
+//       permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+// COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+// OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package org.owasp.encoder;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.ObjectStreamClass;
+import junit.framework.TestCase;
+
+/**
+ * UnsupportedContextException must stay serialization compatible with the
+ * released versions, which all used the JVM-computed serialVersionUID below.
+ */
+public class UnsupportedContextExceptionTest extends TestCase {
+
+    public void testSerialVersionUidMatchesReleasedVersions() {
+        assertEquals(-1517019963198920181L,
+            ObjectStreamClass.lookup(UnsupportedContextException.class).getSerialVersionUID());
+    }
+
+    public void testSerializationRoundTrip() throws Exception {
+        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+        ObjectOutputStream out = new ObjectOutputStream(bytes);
+        out.writeObject(new UnsupportedContextException("no-such-context"));
+        out.close();
+        ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(bytes.toByteArray()));
+        UnsupportedContextException copy = (UnsupportedContextException) in.readObject();
+        assertEquals("no-such-context", copy.getMessage());
+    }
+}
diff --git a/esapi/pom.xml b/esapi/pom.xml
index daa2f32..9a7fc4e 100644
--- a/esapi/pom.xml
+++ b/esapi/pom.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="US-ASCII"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
 ~ Copyright (c) 2015 OWASP.
 ~ All rights reserved.
diff --git a/esapi/src/site/site.xml b/esapi/src/site/site.xml
index 743ef44..acde6a4 100644
--- a/esapi/src/site/site.xml
+++ b/esapi/src/site/site.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="ISO-8859-1"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
 Copyright (c) 2015 Jeremy Long
 All rights reserved.
diff --git a/jakarta/pom.xml b/jakarta/pom.xml
index 413d698..0492127 100644
--- a/jakarta/pom.xml
+++ b/jakarta/pom.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="US-ASCII"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
 ~ Copyright (c) 2015 OWASP.
 ~ All rights reserved.
@@ -86,12 +86,6 @@
             <version>4.0.0</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>jakarta.servlet</groupId>
-            <artifactId>jakarta.servlet-api</artifactId>
-            <version>6.0.0</version>
-            <scope>test</scope>
-        </dependency>
     </dependencies>
 
     <build>
diff --git a/jakarta/src/site/site.xml b/jakarta/src/site/site.xml
index dde2b60..c139af1 100644
--- a/jakarta/src/site/site.xml
+++ b/jakarta/src/site/site.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="ISO-8859-1"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
 Copyright (c) 2015 Jeremy Long
 All rights reserved.
diff --git a/jsp/pom.xml b/jsp/pom.xml
index eea8540..9d1a86e 100644
--- a/jsp/pom.xml
+++ b/jsp/pom.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="US-ASCII"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
 ~ Copyright (c) 2015 OWASP.
 ~ All rights reserved.
@@ -86,12 +86,6 @@
             <version>2.2.5</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>javax.servlet</groupId>
-            <artifactId>javax.servlet-api</artifactId>
-            <version>3.0.1</version>
-            <scope>test</scope>
-        </dependency>
     </dependencies>
 
     <build>
diff --git a/jsp/src/site/site.xml b/jsp/src/site/site.xml
index dde2b60..c139af1 100644
--- a/jsp/src/site/site.xml
+++ b/jsp/src/site/site.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="ISO-8859-1"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
 Copyright (c) 2015 Jeremy Long
 All rights reserved.
diff --git a/pom.xml b/pom.xml
old mode 100755
new mode 100644
index 235ae97..1714e63
--- a/pom.xml
+++ b/pom.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="US-ASCII"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!--
 ~ Copyright (c) 2015 OWASP.
 ~ All rights reserved.
@@ -195,6 +195,11 @@
                     <artifactId>maven-compiler-plugin</artifactId>
                     <version>3.16.0</version>
                 </plugin>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>build-helper-maven-plugin</artifactId>
+                    <version>3.6.2</version>
+                </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-jar-plugin</artifactId>
@@ -358,6 +363,16 @@
                     <release>8</release>
                 </configuration>
                 <executions>
+                    <execution>
+                        <!-- src/main/java9 is a project source root (for the sources JAR)
+                             but must never reach the Java 8 compilation. -->
+                        <id>default-compile</id>
+                        <configuration>
+                            <compileSourceRoots>
+                                <compileSourceRoot>${project.basedir}/src/main/java</compileSourceRoot>
+                            </compileSourceRoots>
+                        </configuration>
+                    </execution>
                     <execution>
                         <id>compile-java-9</id>
                         <phase>compile</phase>
@@ -438,6 +453,25 @@
                     </archive>
                 </configuration>
             </plugin>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>build-helper-maven-plugin</artifactId>
+                <executions>
+                    <execution>
+                        <!-- Makes the sources JAR include the Java 9 module descriptor. -->
+                        <id>add-java9-sources</id>
+                        <phase>generate-sources</phase>
+                        <goals>
+                            <goal>add-source</goal>
+                        </goals>
+                        <configuration>
+                            <sources>
+                                <source>${project.basedir}/src/main/java9</source>
+                            </sources>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-source-plugin</artifactId>
@@ -457,6 +491,9 @@
                 <configuration>
                     <source>8</source>
                     <failOnError>true</failOnError>
+                    <sourceFileExcludes>
+                        <sourceFileExclude>module-info.java</sourceFileExclude>
+                    </sourceFileExcludes>
                 </configuration>
                 <executions>
                     <execution>
@@ -565,6 +602,9 @@
                         <configuration>
                             <source>8</source>
                             <failOnError>true</failOnError>
+                            <sourceFileExcludes>
+                                <sourceFileExclude>module-info.java</sourceFileExclude>
+                            </sourceFileExcludes>
                         </configuration>
                     </reportSet>
                 </reportSets>
diff --git a/src/main/config/checkstyle.xml b/src/main/config/checkstyle.xml
index 0a5f0da..6656e95 100644
--- a/src/main/config/checkstyle.xml
+++ b/src/main/config/checkstyle.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="US-ASCII"?>
+<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE module PUBLIC
     "-//Puppy Crawl//DTD Check Configuration 1.2//EN"
     "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">