diff --git a/android/configured_jars.go b/android/configured_jars.go
new file mode 100644
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+++ b/android/configured_jars.go
@@ -0,0 +1,314 @@
+// Copyright 2022 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package android
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"path/filepath"
+	"strings"
+)
+
+// The ConfiguredJarList struct provides methods for handling a list of (apex, jar) pairs.
+// Such lists are used in the build system for things like bootclasspath jars or system server jars.
+// The apex part is either an apex name, or a special names "platform" or "system_ext". Jar is a
+// module name. The pairs come from Make product variables as a list of colon-separated strings.
+//
+// Examples:
+//   - "com.android.art:core-oj"
+//   - "platform:framework"
+//   - "system_ext:foo"
+type ConfiguredJarList struct {
+	// A list of apex components, which can be an apex name,
+	// or special names like "platform" or "system_ext".
+	apexes []string
+
+	// A list of jar module name components.
+	jars []string
+}
+
+// Len returns the length of the list of jars.
+func (l *ConfiguredJarList) Len() int {
+	return len(l.jars)
+}
+
+// Jar returns the idx-th jar component of (apex, jar) pairs.
+func (l *ConfiguredJarList) Jar(idx int) string {
+	return l.jars[idx]
+}
+
+// Apex returns the idx-th apex component of (apex, jar) pairs.
+func (l *ConfiguredJarList) Apex(idx int) string {
+	return l.apexes[idx]
+}
+
+// ContainsJar returns true if the (apex, jar) pairs contains a pair with the
+// given jar module name.
+func (l *ConfiguredJarList) ContainsJar(jar string) bool {
+	return InList(jar, l.jars)
+}
+
+// If the list contains the given (apex, jar) pair.
+func (l *ConfiguredJarList) containsApexJarPair(apex, jar string) bool {
+	for i := 0; i < l.Len(); i++ {
+		if apex == l.apexes[i] && jar == l.jars[i] {
+			return true
+		}
+	}
+	return false
+}
+
+// ApexOfJar returns the apex component of the first pair with the given jar name on the list, or
+// an empty string if not found.
+func (l *ConfiguredJarList) ApexOfJar(jar string) string {
+	if idx := IndexList(jar, l.jars); idx != -1 {
+		return l.Apex(IndexList(jar, l.jars))
+	}
+	return ""
+}
+
+// IndexOfJar returns the first pair with the given jar name on the list, or -1
+// if not found.
+func (l *ConfiguredJarList) IndexOfJar(jar string) int {
+	return IndexList(jar, l.jars)
+}
+
+func copyAndAppend(list []string, item string) []string {
+	// Create the result list to be 1 longer than the input.
+	result := make([]string, len(list)+1)
+
+	// Copy the whole input list into the result.
+	count := copy(result, list)
+
+	// Insert the extra item at the end.
+	result[count] = item
+
+	return result
+}
+
+// Append an (apex, jar) pair to the list.
+func (l *ConfiguredJarList) Append(apex string, jar string) ConfiguredJarList {
+	// Create a copy of the backing arrays before appending to avoid sharing backing
+	// arrays that are mutated across instances.
+	apexes := copyAndAppend(l.apexes, apex)
+	jars := copyAndAppend(l.jars, jar)
+
+	return ConfiguredJarList{apexes, jars}
+}
+
+// Append a list of (apex, jar) pairs to the list.
+func (l *ConfiguredJarList) AppendList(other *ConfiguredJarList) ConfiguredJarList {
+	apexes := make([]string, 0, l.Len()+other.Len())
+	jars := make([]string, 0, l.Len()+other.Len())
+
+	apexes = append(apexes, l.apexes...)
+	jars = append(jars, l.jars...)
+
+	apexes = append(apexes, other.apexes...)
+	jars = append(jars, other.jars...)
+
+	return ConfiguredJarList{apexes, jars}
+}
+
+// RemoveList filters out a list of (apex, jar) pairs from the receiving list of pairs.
+func (l *ConfiguredJarList) RemoveList(list ConfiguredJarList) ConfiguredJarList {
+	apexes := make([]string, 0, l.Len())
+	jars := make([]string, 0, l.Len())
+
+	for i, jar := range l.jars {
+		apex := l.apexes[i]
+		if !list.containsApexJarPair(apex, jar) {
+			apexes = append(apexes, apex)
+			jars = append(jars, jar)
+		}
+	}
+
+	return ConfiguredJarList{apexes, jars}
+}
+
+// Filter keeps the entries if a jar appears in the given list of jars to keep. Returns a new list
+// and any remaining jars that are not on this list.
+func (l *ConfiguredJarList) Filter(jarsToKeep []string) (ConfiguredJarList, []string) {
+	var apexes []string
+	var jars []string
+
+	for i, jar := range l.jars {
+		if InList(jar, jarsToKeep) {
+			apexes = append(apexes, l.apexes[i])
+			jars = append(jars, jar)
+		}
+	}
+
+	return ConfiguredJarList{apexes, jars}, RemoveListFromList(jarsToKeep, jars)
+}
+
+// CopyOfJars returns a copy of the list of strings containing jar module name
+// components.
+func (l *ConfiguredJarList) CopyOfJars() []string {
+	return CopyOf(l.jars)
+}
+
+// CopyOfApexJarPairs returns a copy of the list of strings with colon-separated
+// (apex, jar) pairs.
+func (l *ConfiguredJarList) CopyOfApexJarPairs() []string {
+	pairs := make([]string, 0, l.Len())
+
+	for i, jar := range l.jars {
+		apex := l.apexes[i]
+		pairs = append(pairs, apex+":"+jar)
+	}
+
+	return pairs
+}
+
+// BuildPaths returns a list of build paths based on the given directory prefix.
+func (l *ConfiguredJarList) BuildPaths(ctx PathContext, dir OutputPath) WritablePaths {
+	paths := make(WritablePaths, l.Len())
+	for i, jar := range l.jars {
+		paths[i] = dir.Join(ctx, ModuleStem(jar)+".jar")
+	}
+	return paths
+}
+
+// BuildPathsByModule returns a map from module name to build paths based on the given directory
+// prefix.
+func (l *ConfiguredJarList) BuildPathsByModule(ctx PathContext, dir OutputPath) map[string]WritablePath {
+	paths := map[string]WritablePath{}
+	for _, jar := range l.jars {
+		paths[jar] = dir.Join(ctx, ModuleStem(jar)+".jar")
+	}
+	return paths
+}
+
+// UnmarshalJSON converts JSON configuration from raw bytes into a
+// ConfiguredJarList structure.
+func (l *ConfiguredJarList) UnmarshalJSON(b []byte) error {
+	// Try and unmarshal into a []string each item of which contains a pair
+	// <apex>:<jar>.
+	var list []string
+	err := json.Unmarshal(b, &list)
+	if err != nil {
+		// Did not work so return
+		return err
+	}
+
+	apexes, jars, err := splitListOfPairsIntoPairOfLists(list)
+	if err != nil {
+		return err
+	}
+	l.apexes = apexes
+	l.jars = jars
+	return nil
+}
+
+func (l *ConfiguredJarList) MarshalJSON() ([]byte, error) {
+	if len(l.apexes) != len(l.jars) {
+		return nil, errors.New(fmt.Sprintf("Inconsistent ConfiguredJarList: apexes: %q, jars: %q", l.apexes, l.jars))
+	}
+
+	list := make([]string, 0, len(l.apexes))
+
+	for i := 0; i < len(l.apexes); i++ {
+		list = append(list, l.apexes[i]+":"+l.jars[i])
+	}
+
+	return json.Marshal(list)
+}
+
+// ModuleStem hardcodes the stem of framework-minus-apex to return "framework".
+//
+// TODO(b/139391334): hard coded until we find a good way to query the stem of a
+// module before any other mutators are run.
+func ModuleStem(module string) string {
+	if module == "framework-minus-apex" {
+		return "framework"
+	}
+	return module
+}
+
+// DevicePaths computes the on-device paths for the list of (apex, jar) pairs,
+// based on the operating system.
+func (l *ConfiguredJarList) DevicePaths(cfg Config, ostype OsType) []string {
+	paths := make([]string, l.Len())
+	for i, jar := range l.jars {
+		apex := l.apexes[i]
+		name := ModuleStem(jar) + ".jar"
+
+		var subdir string
+		if apex == "platform" {
+			subdir = "system/framework"
+		} else if apex == "system_ext" {
+			subdir = "system_ext/framework"
+		} else {
+			subdir = filepath.Join("apex", apex, "javalib")
+		}
+
+		if ostype.Class == Host {
+			paths[i] = filepath.Join(cfg.Getenv("OUT_DIR"), "host", cfg.PrebuiltOS(), subdir, name)
+		} else {
+			paths[i] = filepath.Join("/", subdir, name)
+		}
+	}
+	return paths
+}
+
+func (l *ConfiguredJarList) String() string {
+	var pairs []string
+	for i := 0; i < l.Len(); i++ {
+		pairs = append(pairs, l.apexes[i]+":"+l.jars[i])
+	}
+	return strings.Join(pairs, ",")
+}
+
+func splitListOfPairsIntoPairOfLists(list []string) ([]string, []string, error) {
+	// Now we need to populate this list by splitting each item in the slice of
+	// pairs and appending them to the appropriate list of apexes or jars.
+	apexes := make([]string, len(list))
+	jars := make([]string, len(list))
+
+	for i, apexjar := range list {
+		apex, jar, err := splitConfiguredJarPair(apexjar)
+		if err != nil {
+			return nil, nil, err
+		}
+		apexes[i] = apex
+		jars[i] = jar
+	}
+
+	return apexes, jars, nil
+}
+
+// Expected format for apexJarValue = <apex name>:<jar name>
+func splitConfiguredJarPair(str string) (string, string, error) {
+	pair := strings.SplitN(str, ":", 2)
+	if len(pair) == 2 {
+		apex := pair[0]
+		jar := pair[1]
+		if apex == "" {
+			return apex, jar, fmt.Errorf("invalid apex '%s' in <apex>:<jar> pair '%s', expected format: <apex>:<jar>", apex, str)
+		}
+		return apex, jar, nil
+	} else {
+		return "error-apex", "error-jar", fmt.Errorf("malformed (apex, jar) pair: '%s', expected format: <apex>:<jar>", str)
+	}
+}
+
+// EmptyConfiguredJarList returns an empty jar list.
+func EmptyConfiguredJarList() ConfiguredJarList {
+	return ConfiguredJarList{}
+}
+
+var earlyBootJarsKey = NewOnceKey("earlyBootJars")