diff --git a/runtime/src/main/java/org/capnproto/AnyPointer.java b/runtime/src/main/java/org/capnproto/AnyPointer.java
index 8f750cb..1094d3a 100644
--- a/runtime/src/main/java/org/capnproto/AnyPointer.java
+++ b/runtime/src/main/java/org/capnproto/AnyPointer.java
@@ -48,7 +48,7 @@ public final class AnyPointer {
     }
     public static final Factory factory = new Factory();
 
-    public final static class Reader extends Capability.ReaderContext {
+    public final static class Reader extends CapTableReader.ReaderContext {
         final SegmentReader segment;
         final int pointer; // offset in words
         final int nestingLimit;
@@ -67,7 +67,7 @@ public final class AnyPointer {
         }
 
         final Reader imbue(CapTableReader capTable) {
-            var result = new Reader(segment, pointer, nestingLimit);
+            Reader result = new Reader(segment, pointer, nestingLimit);
             result.capTable = capTable;
             return result;
         }
@@ -83,9 +83,9 @@ public final class AnyPointer {
         public final ClientHook getPipelinedCap(short[] ops) {
             AnyPointer.Reader any = this;
 
-            for (var pointerIndex: ops) {
+            for (short pointerIndex: ops) {
                 if (pointerIndex >= 0) {
-                    var reader = WireHelpers.readStructPointer(any.segment, any.capTable, any.pointer, null, 0, any.nestingLimit);
+                    StructReader reader = WireHelpers.readStructPointer(any.segment, any.capTable, any.pointer, null, 0, any.nestingLimit);
                     any = reader._getPointerField(AnyPointer.factory, pointerIndex);
                 }
             }
@@ -93,7 +93,7 @@ public final class AnyPointer {
         }
     }
 
-    public static final class Builder extends Capability.BuilderContext {
+    public static final class Builder extends CapTableBuilder.BuilderContext {
         final SegmentBuilder segment;
         final int pointer;
 
@@ -176,7 +176,7 @@ public final class AnyPointer {
         }
 
         public Pipeline getPointerField(short pointerIndex) {
-            var newOps = new short[this.ops.length + 1];
+            short[] newOps = new short[this.ops.length + 1];
             System.arraycopy(this.ops, 0, newOps, 0, this.ops.length);
             newOps[this.ops.length] = pointerIndex;
             return new Pipeline(this.hook, newOps);
diff --git a/runtime/src/main/java/org/capnproto/CapTableBuilder.java b/runtime/src/main/java/org/capnproto/CapTableBuilder.java
index 01e6825..8f137a7 100644
--- a/runtime/src/main/java/org/capnproto/CapTableBuilder.java
+++ b/runtime/src/main/java/org/capnproto/CapTableBuilder.java
@@ -1,6 +1,11 @@
 package org.capnproto;
 
 public interface CapTableBuilder extends CapTableReader {
+
+    class BuilderContext {
+        public CapTableBuilder capTable;
+    }
+
     int injectCap(ClientHook cap);
 
     void dropCap(int index);
diff --git a/runtime/src/main/java/org/capnproto/CapTableReader.java b/runtime/src/main/java/org/capnproto/CapTableReader.java
index e8f5be5..b6d6f8d 100644
--- a/runtime/src/main/java/org/capnproto/CapTableReader.java
+++ b/runtime/src/main/java/org/capnproto/CapTableReader.java
@@ -1,5 +1,10 @@
 package org.capnproto;
 
 public interface CapTableReader {
+
+    class ReaderContext {
+        public CapTableReader capTable;
+    }
+
     ClientHook extractCap(int index);
 }
diff --git a/runtime/src/main/java/org/capnproto/Capability.java b/runtime/src/main/java/org/capnproto/Capability.java
index 8fc0f7a..4521c54 100644
--- a/runtime/src/main/java/org/capnproto/Capability.java
+++ b/runtime/src/main/java/org/capnproto/Capability.java
@@ -5,19 +5,11 @@ import java.util.*;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.CompletionStage;
 
+import static org.capnproto.ClientHook.BROKEN_CAPABILITY_BRAND;
+import static org.capnproto.ClientHook.NULL_CAPABILITY_BRAND;
+
 public final class Capability {
 
-    static final Object NULL_CAPABILITY_BRAND = new Object();
-    static final Object BROKEN_CAPABILITY_BRAND = new Object();
-
-    public static class BuilderContext {
-        public CapTableBuilder capTable;
-    }
-
-    public static class ReaderContext {
-        public CapTableReader capTable;
-    }
-
     public static abstract class Factory<T extends ClientBase>
             implements FromPointerReader<T>,
                        FromPointerBuilder<T>,
diff --git a/runtime/src/main/java/org/capnproto/ClientHook.java b/runtime/src/main/java/org/capnproto/ClientHook.java
index d04e125..ed4b320 100644
--- a/runtime/src/main/java/org/capnproto/ClientHook.java
+++ b/runtime/src/main/java/org/capnproto/ClientHook.java
@@ -5,6 +5,8 @@ import java.util.concurrent.CompletableFuture;
 
 public interface ClientHook {
 
+    static final Object NULL_CAPABILITY_BRAND = new Object();
+    static final Object BROKEN_CAPABILITY_BRAND = new Object();
     /**
      * Start a new call, allowing the client to allocate request/response objects as it sees fit.
      * This version is used when calls are made from application code in the local process.
@@ -59,7 +61,7 @@ public interface ClientHook {
      *  Repeatedly calls whenMoreResolved() until it returns nullptr.
      */
     default CompletableFuture<java.lang.Void> whenResolved() {
-        var promise = whenMoreResolved();
+        CompletableFuture<ClientHook> promise = whenMoreResolved();
         return promise != null
                 ? promise.thenCompose(ClientHook::whenResolved)
                 : CompletableFuture.completedFuture(null);
@@ -70,18 +72,18 @@ public interface ClientHook {
      * reading a null pointer out of a Cap'n Proto message.
      */
     default boolean isNull() {
-        return getBrand() == Capability.NULL_CAPABILITY_BRAND;
+        return getBrand() == NULL_CAPABILITY_BRAND;
     }
 
     /**
      * Returns true if the capability was created by newBrokenCap().
      */
     default boolean isError() {
-        return getBrand() == Capability.BROKEN_CAPABILITY_BRAND;
+        return getBrand() == BROKEN_CAPABILITY_BRAND;
     }
 
     /**
-     *  Implements {@link Capability.Client.getFd}. If this returns null but whenMoreResolved() returns
+     *  Implements Capability.Client.getFd. If this returns null but whenMoreResolved() returns
      *  non-null, then Capability::Client::getFd() waits for resolution and tries again.
      */
     default FileDescriptor getFd() {
diff --git a/runtime/src/main/java/org/capnproto/ExportTable.java b/runtime/src/main/java/org/capnproto/ExportTable.java
index dcd7730..8cb7089 100644
--- a/runtime/src/main/java/org/capnproto/ExportTable.java
+++ b/runtime/src/main/java/org/capnproto/ExportTable.java
@@ -19,7 +19,7 @@ abstract class ExportTable<T> implements Iterable<T> {
     }
 
     public T erase(int id, T entry) {
-        var value = slots.get(id);
+        T value = slots.get(id);
         if (value == entry) {
             freeIds.add(id);
             return slots.remove(id);
@@ -30,8 +30,8 @@ abstract class ExportTable<T> implements Iterable<T> {
 
     public T next() {
         int id = freeIds.isEmpty() ? max++ : freeIds.remove();
-        var value = newExportable(id);
-        var prev = slots.put(id, value);
+        T value = newExportable(id);
+        T prev = slots.put(id, value);
         assert prev == null;
         return value;
     }
diff --git a/runtime/src/main/java/org/capnproto/ImportTable.java b/runtime/src/main/java/org/capnproto/ImportTable.java
index 6905060..970dee8 100644
--- a/runtime/src/main/java/org/capnproto/ImportTable.java
+++ b/runtime/src/main/java/org/capnproto/ImportTable.java
@@ -19,7 +19,7 @@ abstract class ImportTable<T> implements Iterable<T> {
     }
 
     public T erase(int id, T entry) {
-        var removed = slots.remove(id, entry);
+        boolean removed = slots.remove(id, entry);
         assert removed;
         return entry;
     }
diff --git a/runtime/src/main/java/org/capnproto/ListBuilder.java b/runtime/src/main/java/org/capnproto/ListBuilder.java
index 19f3c59..9d20018 100644
--- a/runtime/src/main/java/org/capnproto/ListBuilder.java
+++ b/runtime/src/main/java/org/capnproto/ListBuilder.java
@@ -23,7 +23,7 @@ package org.capnproto;
 
 import java.util.List;
 
-public class ListBuilder extends Capability.BuilderContext {
+public class ListBuilder extends CapTableBuilder.BuilderContext {
     public interface Factory<T> {
         T constructBuilder(SegmentBuilder segment, int ptr,
                            int elementCount, int step,
@@ -31,9 +31,9 @@ public class ListBuilder extends Capability.BuilderContext {
         default T constructBuilder(SegmentBuilder segment, CapTableBuilder capTable, int ptr,
                            int elementCount, int step,
                            int structDataSize, short structPointerCount) {
-            var result = constructBuilder(segment, ptr, elementCount, step, structDataSize, structPointerCount);
-            if (result instanceof Capability.BuilderContext) {
-                ((Capability.BuilderContext) result).capTable = capTable;
+            T result = constructBuilder(segment, ptr, elementCount, step, structDataSize, structPointerCount);
+            if (result instanceof CapTableBuilder.BuilderContext) {
+                ((CapTableBuilder.BuilderContext) result).capTable = capTable;
             }
             return result;
         }
diff --git a/runtime/src/main/java/org/capnproto/ListReader.java b/runtime/src/main/java/org/capnproto/ListReader.java
index bf1f45c..f63ecfe 100644
--- a/runtime/src/main/java/org/capnproto/ListReader.java
+++ b/runtime/src/main/java/org/capnproto/ListReader.java
@@ -21,7 +21,7 @@
 
 package org.capnproto;
 
-public class ListReader extends Capability.ReaderContext {
+public class ListReader extends CapTableReader.ReaderContext {
     public interface Factory<T> {
         T constructReader(SegmentReader segment,
                           int ptr,
@@ -31,9 +31,9 @@ public class ListReader extends Capability.ReaderContext {
         default T constructReader(SegmentReader segment, CapTableReader capTable, int ptr,
                                   int elementCount, int step,
                                   int structDataSize, short structPointerCount, int nestingLimit) {
-            var result = constructReader(segment, ptr, elementCount, step, structDataSize, structPointerCount, nestingLimit);
-            if (result instanceof Capability.ReaderContext) {
-                ((Capability.ReaderContext) result).capTable = capTable;
+            T result = constructReader(segment, ptr, elementCount, step, structDataSize, structPointerCount, nestingLimit);
+            if (result instanceof CapTableReader.ReaderContext) {
+                ((CapTableReader.ReaderContext) result).capTable = capTable;
             }
             return result;
         }
diff --git a/runtime/src/main/java/org/capnproto/SetPointerBuilder.java b/runtime/src/main/java/org/capnproto/SetPointerBuilder.java
index c1566e1..cdc7f72 100644
--- a/runtime/src/main/java/org/capnproto/SetPointerBuilder.java
+++ b/runtime/src/main/java/org/capnproto/SetPointerBuilder.java
@@ -22,5 +22,8 @@
 package org.capnproto;
 
 public interface SetPointerBuilder<Builder, Reader> {
+    default void setPointerBuilder(SegmentBuilder segment, int pointer, Reader value) {
+        setPointerBuilder(segment, null, pointer, value);
+    }
     void setPointerBuilder(SegmentBuilder segment, CapTableBuilder capTable, int pointer, Reader value);
 }
diff --git a/runtime/src/main/java/org/capnproto/StructBuilder.java b/runtime/src/main/java/org/capnproto/StructBuilder.java
index 6285dce..f954377 100644
--- a/runtime/src/main/java/org/capnproto/StructBuilder.java
+++ b/runtime/src/main/java/org/capnproto/StructBuilder.java
@@ -21,15 +21,15 @@
 
 package org.capnproto;
 
-public class StructBuilder extends Capability.BuilderContext {
+public class StructBuilder extends CapTableBuilder.BuilderContext {
     public interface Factory<T> {
         T constructBuilder(SegmentBuilder segment, int data, int pointers, int dataSize,
                            short pointerCount);
         default T constructBuilder(SegmentBuilder segment, CapTableBuilder capTable, int data, int pointers, int dataSize,
                            short pointerCount) {
-            var result = constructBuilder(segment, data, pointers, dataSize, pointerCount);
-            if (result instanceof Capability.BuilderContext) {
-                ((Capability.BuilderContext) result).capTable = capTable;
+            T result = constructBuilder(segment, data, pointers, dataSize, pointerCount);
+            if (result instanceof CapTableBuilder.BuilderContext) {
+                ((CapTableBuilder.BuilderContext) result).capTable = capTable;
             }
             return result;
         }
diff --git a/runtime/src/main/java/org/capnproto/StructReader.java b/runtime/src/main/java/org/capnproto/StructReader.java
index 3225c71..14532a6 100644
--- a/runtime/src/main/java/org/capnproto/StructReader.java
+++ b/runtime/src/main/java/org/capnproto/StructReader.java
@@ -21,7 +21,7 @@
 
 package org.capnproto;
 
-public class StructReader extends Capability.ReaderContext {
+public class StructReader extends CapTableReader.ReaderContext {
     public interface Factory<T> {
         T constructReader(SegmentReader segment, int data, int pointers,
                                    int dataSize, short pointerCount,
@@ -29,9 +29,9 @@ public class StructReader extends Capability.ReaderContext {
         default T constructReader(SegmentReader segment, CapTableReader capTable, int data, int pointers,
                           int dataSize, short pointerCount,
                           int nestingLimit) {
-            var result = constructReader(segment, data, pointers, dataSize, pointerCount, nestingLimit);
-            if (result instanceof Capability.ReaderContext) {
-                ((Capability.ReaderContext) result).capTable = capTable;
+            T result = constructReader(segment, data, pointers, dataSize, pointerCount, nestingLimit);
+            if (result instanceof CapTableReader.ReaderContext) {
+                ((CapTableReader.ReaderContext) result).capTable = capTable;
             }
             return result;
         }