diff --git a/python/mozbuild/mozbuild/backend/recursivemake.py b/python/mozbuild/mozbuild/backend/recursivemake.py
index fc3f505e280f..88a479edb53f 100644
--- a/python/mozbuild/mozbuild/backend/recursivemake.py
+++ b/python/mozbuild/mozbuild/backend/recursivemake.py
@@ -31,11 +31,13 @@ from ..frontend.data import (
     GeneratedWebIDLFile,
     InstallationTarget,
     IPDLFile,
+    JavaJarData,
     LocalInclude,
     PreprocessedTestWebIDLFile,
     PreprocessedWebIDLFile,
     Program,
     SandboxDerived,
+    SandboxWrapped,
     TestWebIDLFile,
     VariablePassthru,
     XPIDLFile,
@@ -417,6 +419,15 @@ class RecursiveMakeBackend(CommonBackend):
         elif isinstance(obj, InstallationTarget):
             self._process_installation_target(obj, backend_file)
 
+        elif isinstance(obj, SandboxWrapped):
+            # Process a rich build system object from the front-end
+            # as-is.  Please follow precedent and handle CamelCaseData
+            # in a function named _process_camel_case_data.  At some
+            # point in the future, this unwrapping process may be
+            # automated.
+            if isinstance(obj.wrapped, JavaJarData):
+                self._process_java_jar_data(obj.wrapped, backend_file)
+
         self._backend_files[obj.srcdir] = backend_file
 
     def _fill_root_mk(self):
@@ -1004,6 +1015,23 @@ class RecursiveMakeBackend(CommonBackend):
             path = ''
         backend_file.write('LOCAL_INCLUDES += -I%s%s\n' % (path, generated_include))
 
+    def _process_java_jar_data(self, jar, backend_file):
+        target = jar.name
+        backend_file.write('JAVA_JAR_TARGETS += %s\n' % target)
+        backend_file.write('%s_DEST := %s.jar\n' % (target, jar.name))
+        if jar.sources:
+            backend_file.write('%s_JAVAFILES := %s\n' %
+                (target, ' '.join(jar.sources)))
+        if jar.generated_sources:
+            backend_file.write('%s_PP_JAVAFILES := %s\n' %
+                (target, ' '.join(jar.generated_sources)))
+        if jar.extra_jars:
+            backend_file.write('%s_EXTRA_JARS := %s\n' %
+                (target, ' '.join(jar.extra_jars)))
+        if jar.javac_flags:
+            backend_file.write('%s_JAVAC_FLAGS := %s\n' %
+                (target, jar.javac_flags))
+
     def _write_manifests(self, dest, manifests):
         man_dir = os.path.join(self.environment.topobjdir, '_build_manifests',
             dest)
diff --git a/python/mozbuild/mozbuild/frontend/data.py b/python/mozbuild/mozbuild/frontend/data.py
index 8d525212e68a..7307fe10789b 100644
--- a/python/mozbuild/mozbuild/frontend/data.py
+++ b/python/mozbuild/mozbuild/frontend/data.py
@@ -371,6 +371,54 @@ class GeneratedInclude(SandboxDerived):
 
         self.path = path
 
+
+class SandboxWrapped(SandboxDerived):
+    """Generic sandbox container object for a wrapped rich object.
+
+    Use this wrapper class to shuttle a rich build system object
+    completely defined in moz.build files through the tree metadata
+    emitter to the build backend for processing as-is.
+    """
+
+    __slots__ = (
+        'wrapped',
+    )
+
+    def __init__(self, sandbox, wrapped):
+        SandboxDerived.__init__(self, sandbox)
+
+        self.wrapped = wrapped
+
+
+class JavaJarData(object):
+    """Represents a Java JAR file.
+
+    A Java JAR has the following members:
+        * sources - list of input java sources
+        * generated_sources - list of generated input java sources
+        * extra_jars - list of JAR file dependencies to include on the
+          javac compiler classpath
+        * javac_flags - string containing extra flags passed to the
+          javac compiler
+    """
+
+    __slots__ = (
+        'name',
+        'sources',
+        'generated_sources',
+        'extra_jars',
+        'javac_flags',
+    )
+
+    def __init__(self, name, sources=[], generated_sources=[],
+            extra_jars=[], javac_flags=None):
+        self.name = name
+        self.sources = list(sources)
+        self.generated_sources = list(generated_sources)
+        self.extra_jars = list(extra_jars)
+        self.javac_flags = javac_flags
+
+
 class InstallationTarget(SandboxDerived):
     """Describes the rules that affect where files get installed to."""
 
diff --git a/python/mozbuild/mozbuild/frontend/emitter.py b/python/mozbuild/mozbuild/frontend/emitter.py
index 7102a464d45a..9302522efb24 100644
--- a/python/mozbuild/mozbuild/frontend/emitter.py
+++ b/python/mozbuild/mozbuild/frontend/emitter.py
@@ -32,6 +32,7 @@ from .data import (
     PreprocessedWebIDLFile,
     Program,
     ReaderSummary,
+    SandboxWrapped,
     TestWebIDLFile,
     TestManifest,
     VariablePassthru,
@@ -258,6 +259,9 @@ class TreeMetadataEmitter(LoggingMixin):
                 for obj in self._process_test_manifest(sandbox, info, path):
                     yield obj
 
+        for name, jar in sandbox.get('JAVA_JAR_TARGETS', {}).items():
+            yield SandboxWrapped(sandbox, jar)
+
     def _process_test_manifest(self, sandbox, info, manifest_path):
         flavor, install_prefix, filter_inactive = info
 
diff --git a/python/mozbuild/mozbuild/frontend/reader.py b/python/mozbuild/mozbuild/frontend/reader.py
index 45b7f440d8c9..979eaa2cec66 100644
--- a/python/mozbuild/mozbuild/frontend/reader.py
+++ b/python/mozbuild/mozbuild/frontend/reader.py
@@ -40,6 +40,10 @@ from mozbuild.util import (
 
 from mozbuild.backend.configenvironment import ConfigEnvironment
 
+from .data import (
+    JavaJarData,
+)
+
 from .sandbox import (
     SandboxError,
     SandboxExecutionError,
@@ -222,6 +226,22 @@ class MozbuildSandbox(Sandbox):
 
         Sandbox.exec_file(self, path)
 
+    def _add_java_jar(self, name):
+        """Add a Java JAR build target."""
+        if not name:
+            raise Exception('Java JAR cannot be registered without a name')
+
+        if '/' in name or '\\' in name or '.jar' in name:
+            raise Exception('Java JAR names must not include slashes or'
+                ' .jar: %s' % name)
+
+        if self['JAVA_JAR_TARGETS'].has_key(name):
+            raise Exception('Java JAR has already been registered: %s' % name)
+
+        jar = JavaJarData(name)
+        self['JAVA_JAR_TARGETS'][name] = jar
+        return jar
+
     def _add_tier_directory(self, tier, reldir, static=False, external=False):
         """Register a tier directory with the build."""
         if isinstance(reldir, text_type):
diff --git a/python/mozbuild/mozbuild/frontend/sandbox_symbols.py b/python/mozbuild/mozbuild/frontend/sandbox_symbols.py
index 425a4aa3254c..b85a1a40dcf6 100644
--- a/python/mozbuild/mozbuild/frontend/sandbox_symbols.py
+++ b/python/mozbuild/mozbuild/frontend/sandbox_symbols.py
@@ -209,6 +209,13 @@ VARIABLES = {
         """Name of target library generated when cross compiling.
         """, 'binaries'),
 
+    'JAVA_JAR_TARGETS': (dict, dict, {},
+        """Defines Java JAR targets to be built.
+
+        This variable should not be populated directly. Instead, it should
+        populated by calling add_java_jar().
+        """, 'binaries'),
+
     'JS_MODULES_PATH': (unicode, unicode, "",
         """Sub-directory of ``$(FINAL_TARGET)`` to install
         ``EXTRA_JS_MODULES``.
@@ -535,6 +542,19 @@ FUNCTIONS = {
            include('/elsewhere/foo.build')
         """),
 
+    'add_java_jar': ('_add_java_jar', (str,),
+        """Declare a Java JAR target to be built.
+
+        This is the supported way to populate the JAVA_JAR_TARGETS
+        variable.
+
+        The parameters are:
+        * dest - target name, without the trailing .jar. (required)
+
+        This returns a rich Java JAR type, described at
+        :py:class:`mozbuild.frontend.data.JavaJarData`.
+        """),
+
     'add_tier_dir': ('_add_tier_directory', (str, [str, list], bool, bool),
         """Register a directory for tier traversal.