diff --git a/pom.xml b/pom.xml
index e98372e4..8f75acf5 100644
--- a/pom.xml
+++ b/pom.xml
@@ -97,11 +97,6 @@
       <artifactId>joda-time</artifactId>
       <version>2.12.7</version>
     </dependency>
-    <dependency>
-      <groupId>com.google.guava</groupId>
-      <artifactId>guava</artifactId>
-      <version>32.0.1-jre</version>
-    </dependency>
     <dependency>
       <groupId>org.slf4j</groupId>
       <artifactId>slf4j-api</artifactId>
diff --git a/src/main/java/loci/common/Location.java b/src/main/java/loci/common/Location.java
index 8cdef653..8ad2830a 100644
--- a/src/main/java/loci/common/Location.java
+++ b/src/main/java/loci/common/Location.java
@@ -47,13 +47,12 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.regex.Pattern;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.google.common.collect.MapMaker;
-
 /**
  * Pseudo-extension of {@link java.io.File} that supports reading over HTTP
  * (among other things).
@@ -92,7 +91,7 @@ protected class ListingsResult {
     }
   }
   private static final Map<String, ListingsResult> fileListings =
-    new MapMaker().makeMap();  // like Java's ConcurrentHashMap
+    new ConcurrentHashMap<String, ListingsResult>();
 
   /** Pattern to match child URLs */
   private static final Pattern URL_MATCHER = Pattern.compile(
diff --git a/src/main/java/loci/common/RandomAccessOutputStream.java b/src/main/java/loci/common/RandomAccessOutputStream.java
index ff072cbd..0e214afa 100644
--- a/src/main/java/loci/common/RandomAccessOutputStream.java
+++ b/src/main/java/loci/common/RandomAccessOutputStream.java
@@ -39,8 +39,6 @@
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 
-import com.google.common.math.LongMath;
-
 /**
  * RandomAccessOutputStream provides methods for writing to files and
  * byte arrays.
@@ -123,8 +121,7 @@ public void skipBytes(int skip) throws IOException {
     final long currentPosition = outputFile.getFilePointer();
     final long newPosition;
     try {
-      /* in Java 8 can instead use addExact */
-      newPosition = LongMath.checkedAdd(currentPosition, skip);
+      newPosition = Math.addExact(currentPosition, skip);
     } catch (ArithmeticException ae) {
       /* translate to expected checked exception */
       throw new IOException("seek is out of range", ae);