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diff --git a/java/com/google/gerrit/server/config/ScheduleConfig.java b/java/com/google/gerrit/server/config/ScheduleConfig.java
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+// Copyright (C) 2014 The Android Open Source Project
+//
+// 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 com.google.gerrit.server.config;
+
+import static java.time.ZoneId.systemDefault;
+import static java.util.Objects.requireNonNull;
+
+import com.google.auto.value.AutoValue;
+import com.google.auto.value.extension.memoized.Memoized;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.common.Nullable;
+import java.time.DayOfWeek;
+import java.time.Duration;
+import java.time.LocalTime;
+import java.time.ZonedDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+import java.time.temporal.ChronoUnit;
+import java.util.Locale;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+import org.eclipse.jgit.lib.Config;
+
+/**
+ * This class reads a schedule for running a periodic background job from a Git config.
+ *
+ * <p>A schedule configuration consists of two parameters:
+ *
+ * <ul>
+ *   <li>{@code interval}: Interval for running the periodic background job. The interval must be
+ *       larger than zero. The following suffixes are supported to define the time unit for the
+ *       interval:
+ *       <ul>
+ *         <li>{@code s}, {@code sec}, {@code second}, {@code seconds}
+ *         <li>{@code m}, {@code min}, {@code minute}, {@code minutes}
+ *         <li>{@code h}, {@code hr}, {@code hour}, {@code hours}
+ *         <li>{@code d}, {@code day}, {@code days}
+ *         <li>{@code w}, {@code week}, {@code weeks} ({@code 1 week} is treated as {@code 7 days})
+ *         <li>{@code mon}, {@code month}, {@code months} ({@code 1 month} is treated as {@code 30
+ *             days})
+ *         <li>{@code y}, {@code year}, {@code years} ({@code 1 year} is treated as {@code 365
+ *             days})
+ *       </ul>
+ *   <li>{@code startTime}: The start time defines the first execution of the periodic background
+ *       job. If the configured {@code interval} is shorter than {@code startTime - now} the start
+ *       time will be preponed by the maximum integral multiple of {@code interval} so that the
+ *       start time is still in the future. {@code startTime} must have one of the following
+ *       formats:
+ *       <ul>
+ *         <li>{@code <day of week> <hours>:<minutes>}
+ *         <li>{@code <hours>:<minutes>}
+ *       </ul>
+ *       The placeholders can have the following values:
+ *       <ul>
+ *         <li>{@code <day of week>}: {@code Mon}, {@code Tue}, {@code Wed}, {@code Thu}, {@code
+ *             Fri}, {@code Sat}, {@code Sun}
+ *         <li>{@code <hours>}: {@code 00}-{@code 23}
+ *         <li>{@code <minutes>}: {@code 00}-{@code 59}
+ *       </ul>
+ *       The timezone cannot be specified but is always the system default time-zone.
+ * </ul>
+ *
+ * <p>The section and the subsection from which the {@code interval} and {@code startTime}
+ * parameters are read can be configured.
+ *
+ * <p>Examples for a schedule configuration:
+ *
+ * <ul>
+ *   <li>
+ *       <pre>
+ * foo.startTime = Fri 10:30
+ * foo.interval  = 2 day
+ * </pre>
+ *       Assuming that the server is started on {@code Mon 7:00} then {@code startTime - now} is
+ *       {@code 4 days 3:30 hours}. This is larger than the interval hence the start time is
+ *       preponed by the maximum integral multiple of the interval so that start time is still in
+ *       the future, i.e. preponed by 4 days. This yields a start time of {@code Mon 10:30}, next
+ *       executions are {@code Wed 10:30}, {@code Fri 10:30}. etc.
+ *   <li>
+ *       <pre>
+ * foo.startTime = 6:00
+ * foo.interval = 1 day
+ * </pre>
+ *       Assuming that the server is started on {@code Mon 7:00} then this yields the first run on
+ *       next Tuesday at 6:00 and a repetition interval of 1 day.
+ * </ul>
+ */
+@AutoValue
+public abstract class ScheduleConfig {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  @VisibleForTesting static final String KEY_INTERVAL = "interval";
+  @VisibleForTesting static final String KEY_STARTTIME = "startTime";
+
+  private static final long MISSING_CONFIG = -1L;
+  private static final long INVALID_CONFIG = -2L;
+
+  public static Optional<Schedule> createSchedule(Config config, String section) {
+    return builder(config, section).buildSchedule();
+  }
+
+  public static ScheduleConfig.Builder builder(Config config, String section) {
+    return new AutoValue_ScheduleConfig.Builder()
+        .setNow(computeNow())
+        .setKeyInterval(KEY_INTERVAL)
+        .setKeyStartTime(KEY_STARTTIME)
+        .setConfig(config)
+        .setSection(section);
+  }
+
+  abstract Config config();
+
+  abstract String section();
+
+  @Nullable
+  abstract String subsection();
+
+  abstract String keyInterval();
+
+  abstract String keyStartTime();
+
+  abstract ZonedDateTime now();
+
+  @Memoized
+  public Optional<Schedule> schedule() {
+    long interval = computeInterval(config(), section(), subsection(), keyInterval());
+
+    long initialDelay;
+    if (interval > 0) {
+      initialDelay =
+          computeInitialDelay(config(), section(), subsection(), keyStartTime(), now(), interval);
+    } else {
+      initialDelay = interval;
+    }
+
+    if (isInvalidOrMissing(interval, initialDelay)) {
+      return Optional.empty();
+    }
+
+    return Optional.of(Schedule.create(interval, initialDelay));
+  }
+
+  private boolean isInvalidOrMissing(long interval, long initialDelay) {
+    String key = section() + (subsection() != null ? "." + subsection() : "");
+    if (interval == MISSING_CONFIG && initialDelay == MISSING_CONFIG) {
+      logger.atInfo().log("No schedule configuration for \"%s\".", key);
+      return true;
+    }
+
+    if (interval == MISSING_CONFIG) {
+      logger.atSevere().log(
+          "Incomplete schedule configuration for \"%s\" is ignored. Missing value for \"%s\".",
+          key, key + "." + keyInterval());
+      return true;
+    }
+
+    if (initialDelay == MISSING_CONFIG) {
+      logger.atSevere().log(
+          "Incomplete schedule configuration for \"%s\" is ignored. Missing value for \"%s\".",
+          key, key + "." + keyStartTime());
+      return true;
+    }
+
+    if (interval <= 0 || initialDelay < 0) {
+      logger.atSevere().log("Invalid schedule configuration for \"%s\" is ignored. ", key);
+      return true;
+    }
+
+    return false;
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder b = new StringBuilder();
+    b.append(formatValue(keyInterval()));
+    b.append(", ");
+    b.append(formatValue(keyStartTime()));
+    return b.toString();
+  }
+
+  private String formatValue(String key) {
+    StringBuilder b = new StringBuilder();
+    b.append(section());
+    if (subsection() != null) {
+      b.append(".");
+      b.append(subsection());
+    }
+    b.append(".");
+    b.append(key);
+    String value = config().getString(section(), subsection(), key);
+    if (value != null) {
+      b.append(" = ");
+      b.append(value);
+    } else {
+      b.append(": NA");
+    }
+    return b.toString();
+  }
+
+  private static long computeInterval(
+      Config rc, String section, String subsection, String keyInterval) {
+    try {
+      return ConfigUtil.getTimeUnit(
+          rc, section, subsection, keyInterval, MISSING_CONFIG, TimeUnit.MILLISECONDS);
+    } catch (IllegalArgumentException e) {
+      return INVALID_CONFIG;
+    }
+  }
+
+  private static long computeInitialDelay(
+      Config rc,
+      String section,
+      String subsection,
+      String keyStartTime,
+      ZonedDateTime now,
+      long interval) {
+    String start = rc.getString(section, subsection, keyStartTime);
+    if (start == null) {
+      return MISSING_CONFIG;
+    }
+    return computeInitialDelay(interval, start, now);
+  }
+
+  private static long computeInitialDelay(long interval, String start) {
+    return computeInitialDelay(interval, start, computeNow());
+  }
+
+  private static long computeInitialDelay(long interval, String start, ZonedDateTime now) {
+    requireNonNull(start);
+
+    try {
+      DateTimeFormatter formatter = DateTimeFormatter.ofPattern("[E ]HH:mm").withLocale(Locale.US);
+      LocalTime firstStartTime = LocalTime.parse(start, formatter);
+      ZonedDateTime startTime = now.with(firstStartTime);
+      try {
+        DayOfWeek dayOfWeek = formatter.parse(start, DayOfWeek::from);
+        startTime = startTime.with(dayOfWeek);
+      } catch (DateTimeParseException ignored) {
+        // Day of week is an optional parameter.
+      }
+      startTime = startTime.truncatedTo(ChronoUnit.MINUTES);
+      long delay = Duration.between(now, startTime).toMillis() % interval;
+      if (delay <= 0) {
+        delay += interval;
+      }
+      return delay;
+    } catch (DateTimeParseException e) {
+      return INVALID_CONFIG;
+    }
+  }
+
+  private static ZonedDateTime computeNow() {
+    return ZonedDateTime.now(systemDefault());
+  }
+
+  @AutoValue.Builder
+  public abstract static class Builder {
+    public abstract Builder setConfig(Config config);
+
+    public abstract Builder setSection(String section);
+
+    public abstract Builder setSubsection(@Nullable String subsection);
+
+    public abstract Builder setKeyInterval(String keyInterval);
+
+    public abstract Builder setKeyStartTime(String keyStartTime);
+
+    @VisibleForTesting
+    abstract Builder setNow(ZonedDateTime now);
+
+    abstract ScheduleConfig build();
+
+    public Optional<Schedule> buildSchedule() {
+      return build().schedule();
+    }
+  }
+
+  @AutoValue
+  public abstract static class Schedule {
+    /** Number of milliseconds between events. */
+    public abstract long interval();
+
+    /**
+     * Milliseconds between constructor invocation and first event time.
+     *
+     * <p>If there is any lag between the constructor invocation and queuing the object into an
+     * executor the event will run later, as there is no method to adjust for the scheduling delay.
+     */
+    public abstract long initialDelay();
+
+    /**
+     * Creates a schedule.
+     *
+     * <p>{@link ScheduleConfig} defines details about which values are valid for the {@code
+     * interval} and {@code startTime} parameters.
+     *
+     * @param interval the interval in milliseconds
+     * @param startTime the start time as "{@code <day of week> <hours>:<minutes>}" or "{@code
+     *     <hours>:<minutes>}"
+     * @return the schedule
+     * @throws IllegalArgumentException if any of the parameters is invalid
+     */
+    public static Schedule createOrFail(long interval, String startTime) {
+      return create(interval, startTime).orElseThrow(IllegalArgumentException::new);
+    }
+
+    /**
+     * Creates a schedule.
+     *
+     * <p>{@link ScheduleConfig} defines details about which values are valid for the {@code
+     * interval} and {@code startTime} parameters.
+     *
+     * @param interval the interval in milliseconds
+     * @param startTime the start time as "{@code <day of week> <hours>:<minutes>}" or "{@code
+     *     <hours>:<minutes>}"
+     * @return the schedule or {@link Optional#empty()} if any of the parameters is invalid
+     */
+    public static Optional<Schedule> create(long interval, String startTime) {
+      long initialDelay = computeInitialDelay(interval, startTime);
+      if (interval <= 0 || initialDelay < 0) {
+        return Optional.empty();
+      }
+      return Optional.of(create(interval, initialDelay));
+    }
+
+    static Schedule create(long interval, long initialDelay) {
+      return new AutoValue_ScheduleConfig_Schedule(interval, initialDelay);
+    }
+  }
+}