diff --git a/xwords4/android/XWords4/jni/andglobals.h b/xwords4/android/XWords4/jni/andglobals.h
index 2fdb74420..19efedbee 100644
--- a/xwords4/android/XWords4/jni/andglobals.h
+++ b/xwords4/android/XWords4/jni/andglobals.h
@@ -24,6 +24,8 @@
 #include "dictnry.h"
 #include "game.h"
 
+typedef struct _JNIState JNIState;
+
 typedef struct _AndGlobals {
     VTableMgr* vtMgr;
     CurGameInfo* gi;
@@ -31,7 +33,12 @@ typedef struct _AndGlobals {
     XW_UtilCtxt* util;
     struct JNIUtilCtxt* jniutil;
     TransportProcs* xportProcs;
-    struct JNIState* state;
+    JNIState* state;
 } AndGlobals;
 
+typedef struct _EnvThreadInfo EnvThreadInfo;
+
+JNIEnv* envForMe( EnvThreadInfo* ti, const char* caller );
+#define ENVFORME( ti ) envForMe( (ti), __func__ )
+
 #endif
diff --git a/xwords4/android/XWords4/jni/drawwrapper.c b/xwords4/android/XWords4/jni/drawwrapper.c
index f13e324b5..6790f188c 100644
--- a/xwords4/android/XWords4/jni/drawwrapper.c
+++ b/xwords4/android/XWords4/jni/drawwrapper.c
@@ -37,7 +37,7 @@ enum {
 
 typedef struct _AndDraw {
     DrawCtxVTable* vtable;
-    JNIEnv** env;
+    EnvThreadInfo* ti;
     jobject jdraw;             /* global ref; free it! */
     XP_LangCode curLang;
     jobject jCache[JCACHE_COUNT];
@@ -48,7 +48,7 @@ typedef struct _AndDraw {
 static jobject
 makeJRect( AndDraw* draw, int indx, const XP_Rect* rect )
 {
-    JNIEnv* env = *draw->env;
+    JNIEnv* env = ENVFORME( draw->ti );
     jobject robj = draw->jCache[indx];
     int right = rect->left + rect->width;
     int bottom = rect->top + rect->height;
@@ -87,7 +87,7 @@ static jobject
 makeJRects( AndDraw* draw, int indx, XP_U16 nPlayers, const XP_Rect rects[] )
 {
     XP_U16 ii;
-    JNIEnv* env = *draw->env;
+    JNIEnv* env = ENVFORME( draw->ti );
     jobject jrects = draw->jCache[indx];
     if ( !jrects ) {
         jclass rclass = (*env)->FindClass( env, "android/graphics/Rect");
@@ -122,7 +122,7 @@ static jobject
 makeDSIs( AndDraw* draw, int indx, XP_U16 nPlayers, const DrawScoreInfo dsis[] )
 {
     XP_U16 ii;
-    JNIEnv* env = *draw->env;
+    JNIEnv* env = ENVFORME( draw->ti );
     jobject dsiobjs = draw->jCache[indx];
 
     if ( !dsiobjs ) {
@@ -164,7 +164,7 @@ makeDSIs( AndDraw* draw, int indx, XP_U16 nPlayers, const DrawScoreInfo dsis[] )
 static jobject
 makeDSI( AndDraw* draw, int indx, const DrawScoreInfo* dsi )
 {
-    JNIEnv* env = *draw->env;
+    JNIEnv* env = ENVFORME( draw->ti );
     jobject dsiobj = draw->jCache[indx];
 
     if ( !dsiobj ) {
@@ -193,7 +193,7 @@ makeDSI( AndDraw* draw, int indx, const DrawScoreInfo* dsi )
 
 #define DRAW_CBK_HEADER(nam,sig)                                \
     AndDraw* draw = (AndDraw*)dctx;                             \
-    JNIEnv* env = *draw->env;                                   \
+    JNIEnv* env = ENVFORME( draw->ti );                         \
     XP_ASSERT( !!draw->jdraw );                                 \
     jmethodID mid = getMethodID( env, draw->jdraw, nam, sig );
 
@@ -600,15 +600,15 @@ draw_doNothing( DrawCtx* dctx, ... )
 } /* draw_doNothing */
 
 DrawCtx* 
-makeDraw( MPFORMAL JNIEnv** envp, jobject jdraw )
+makeDraw( MPFORMAL EnvThreadInfo* ti, jobject jdraw )
 {
     AndDraw* draw = (AndDraw*)XP_CALLOC( mpool, sizeof(*draw) );
-    JNIEnv* env = *envp;
+    JNIEnv* env = ENVFORME( ti );
     draw->vtable = XP_MALLOC( mpool, sizeof(*draw->vtable) );
     if ( NULL != jdraw ) {
         draw->jdraw = (*env)->NewGlobalRef( env, jdraw );
     }
-    draw->env = envp;
+    draw->ti = ti;
     MPASSIGN( draw->mpool, mpool );
 
     int ii;
@@ -659,7 +659,7 @@ destroyDraw( DrawCtx** dctx )
 {
     if ( !!*dctx ) {
         AndDraw* draw = (AndDraw*)*dctx;
-        JNIEnv* env = *draw->env;
+        JNIEnv* env = ENVFORME( draw->ti );
         if ( NULL != draw->jdraw ) {
             (*env)->DeleteGlobalRef( env, draw->jdraw );
         }
diff --git a/xwords4/android/XWords4/jni/drawwrapper.h b/xwords4/android/XWords4/jni/drawwrapper.h
index ca02dce09..c6d52474b 100644
--- a/xwords4/android/XWords4/jni/drawwrapper.h
+++ b/xwords4/android/XWords4/jni/drawwrapper.h
@@ -25,7 +25,9 @@
 
 #include "draw.h"
 
-DrawCtx* makeDraw( MPFORMAL JNIEnv** env, jobject j_draw );
+#include "andglobals.h"
+
+DrawCtx* makeDraw( MPFORMAL EnvThreadInfo* ti, jobject j_draw );
 void destroyDraw( DrawCtx** dctx );
 
 
diff --git a/xwords4/android/XWords4/jni/jniutlswrapper.c b/xwords4/android/XWords4/jni/jniutlswrapper.c
index 5fa50cae3..b8896cadc 100644
--- a/xwords4/android/XWords4/jni/jniutlswrapper.c
+++ b/xwords4/android/XWords4/jni/jniutlswrapper.c
@@ -24,17 +24,17 @@
 
 
 struct JNIUtilCtxt {
-    JNIEnv** envp;
+    EnvThreadInfo* ti;
     jobject jjniutil;
     MPSLOT;
 };
 
 JNIUtilCtxt* 
-makeJNIUtil( MPFORMAL JNIEnv** envp, jobject jniutls )
+makeJNIUtil( MPFORMAL EnvThreadInfo* ti, jobject jniutls )
 {
     JNIUtilCtxt* ctxt = (JNIUtilCtxt*)XP_CALLOC( mpool, sizeof( *ctxt ) );
-    JNIEnv* env = *envp;
-    ctxt->envp = envp;
+    ctxt->ti = ti;
+    JNIEnv* env = ENVFORME( ti );
     ctxt->jjniutil = (*env)->NewGlobalRef( env, jniutls );
     MPASSIGN( ctxt->mpool, mpool );
     return ctxt;
@@ -45,7 +45,7 @@ destroyJNIUtil( JNIUtilCtxt** ctxtp )
 {
     JNIUtilCtxt* ctxt = *ctxtp;
     if ( !!ctxt ) {
-        JNIEnv* env = *ctxt->envp;
+        JNIEnv* env = ENVFORME( ctxt->ti );
         (*env)->DeleteGlobalRef( env, ctxt->jjniutil );
         XP_FREE( ctxt->mpool, ctxt );
         *ctxtp = NULL;
@@ -59,7 +59,7 @@ and_util_makeJBitmap( JNIUtilCtxt* jniutil, int nCols, int nRows,
                       const jboolean* colors )
 {
     jobject bitmap;
-    JNIEnv* env = *jniutil->envp;
+    JNIEnv* env = ENVFORME( jniutil->ti );
     jmethodID mid
         = getMethodID( env, jniutil->jjniutil, "makeBitmap", 
                        "(II[Z)Landroid/graphics/drawable/BitmapDrawable;" );
@@ -79,7 +79,7 @@ and_util_splitFaces( JNIUtilCtxt* jniutil, const XP_U8* bytes, jsize len,
                      XP_Bool isUTF8 )
 {
     jobject strarray = NULL;
-    JNIEnv* env = *jniutil->envp;
+    JNIEnv* env = ENVFORME( jniutil->ti );
     jmethodID mid
         = getMethodID( env, jniutil->jjniutil, "splitFaces",
                        "([BZ)[[Ljava/lang/String;" );
@@ -96,7 +96,7 @@ jstring
 and_util_getMD5SumForDict( JNIUtilCtxt* jniutil, const XP_UCHAR* name,
                            const XP_U8* bytes, jsize len )
 {
-    JNIEnv* env = *jniutil->envp;
+    JNIEnv* env = ENVFORME( jniutil->ti );
     jmethodID mid = getMethodID( env, jniutil->jjniutil, "getMD5SumFor",
                                  "(Ljava/lang/String;[B)Ljava/lang/String;" );
     jstring jname = (*env)->NewStringUTF( env, name );
@@ -112,7 +112,7 @@ and_util_getMD5SumForDict( JNIUtilCtxt* jniutil, const XP_UCHAR* name,
 jstring
 and_util_getMD5SumForBytes( JNIUtilCtxt* jniutil, const XP_U8* bytes, jsize len )
 {
-    JNIEnv* env = *jniutil->envp;
+    JNIEnv* env = ENVFORME( jniutil->ti );
     jmethodID mid = getMethodID( env, jniutil->jjniutil, "getMD5SumFor",
                                  "([B)Ljava/lang/String;" );
 
diff --git a/xwords4/android/XWords4/jni/jniutlswrapper.h b/xwords4/android/XWords4/jni/jniutlswrapper.h
index a918ba3ba..66892f3b2 100644
--- a/xwords4/android/XWords4/jni/jniutlswrapper.h
+++ b/xwords4/android/XWords4/jni/jniutlswrapper.h
@@ -28,7 +28,7 @@
 
 typedef struct JNIUtilCtxt JNIUtilCtxt;
 
-JNIUtilCtxt* makeJNIUtil( MPFORMAL JNIEnv** env, jobject jniutls );
+JNIUtilCtxt* makeJNIUtil( MPFORMAL EnvThreadInfo* ti, jobject jniutls );
 void destroyJNIUtil( JNIUtilCtxt** jniu );
 
 jobject and_util_makeJBitmap( JNIUtilCtxt* jniu, int nCols, int nRows, 
diff --git a/xwords4/android/XWords4/jni/utilwrapper.c b/xwords4/android/XWords4/jni/utilwrapper.c
index 230a591d2..63e8475ff 100644
--- a/xwords4/android/XWords4/jni/utilwrapper.c
+++ b/xwords4/android/XWords4/jni/utilwrapper.c
@@ -35,7 +35,7 @@ typedef struct _TimerStorage {
 
 typedef struct _AndUtil {
     XW_UtilCtxt util;
-    JNIEnv** env;
+    EnvThreadInfo* ti;
     jobject jutil;  /* global ref to object implementing XW_UtilCtxt */
     TimerStorage timerStorage[NUM_TIMERS_PLUS_ONE];
     XP_UCHAR* userStrings[N_AND_USER_STRINGS];
@@ -70,7 +70,7 @@ and_util_makeStreamFromAddr( XW_UtilCtxt* uc, XP_PlayerAddr channelNo )
 
 #define UTIL_CBK_HEADER(nam,sig)                                        \
     AndUtil* util = (AndUtil*)uc;                                       \
-    JNIEnv* env = *util->env;                                           \
+    JNIEnv* env = ENVFORME( util->ti );                                 \
     if ( NULL != util->jutil ) {                                        \
         jmethodID mid = getMethodID( env, util->jutil, nam, sig )
 
@@ -376,7 +376,7 @@ XP_U32
 and_util_getCurSeconds( XW_UtilCtxt* uc )
 {
     AndUtil* andutil = (AndUtil*)uc;
-    XP_U32 curSeconds = getCurSeconds( *andutil->env );
+    XP_U32 curSeconds = getCurSeconds( ENVFORME( andutil->ti ) );
     /* struct timeval tv; */
     /* gettimeofday( &tv, NULL ); */
     /* XP_LOGF( "%s: %d vs %d", __func__, (int)tv.tv_sec, (int)curSeconds ); */
@@ -394,7 +394,7 @@ and_util_makeEmptyDict( XW_UtilCtxt* uc )
     AndUtil* andutil = (AndUtil*)uc;
     DictionaryCtxt* result =  
         and_dictionary_make_empty( MPPARM( ((AndUtil*)uc)->util.mpool )
-                                   *andutil->env, globals->jniutil );
+                                   ENVFORME( andutil->ti ), globals->jniutil );
     return dict_ref( result );
 #endif
 }
@@ -637,7 +637,7 @@ static XP_UCHAR*
 and_util_md5sum( XW_UtilCtxt* uc, const XP_U8* ptr, XP_U16 len )
 {
     AndUtil* util = (AndUtil*)uc;
-    JNIEnv* env = *util->env;
+    JNIEnv* env = ENVFORME( util->ti );
     AndGlobals* globals = (AndGlobals*)uc->closure;
     struct JNIUtilCtxt* jniutil = globals->jniutil;
     jstring jsum = and_util_getMD5SumForBytes( jniutil, ptr, len );
@@ -649,13 +649,13 @@ and_util_md5sum( XW_UtilCtxt* uc, const XP_U8* ptr, XP_U16 len )
 
 
 XW_UtilCtxt*
-makeUtil( MPFORMAL JNIEnv** envp, jobject jutil, CurGameInfo* gi, 
+makeUtil( MPFORMAL EnvThreadInfo* ti, jobject jutil, CurGameInfo* gi, 
           AndGlobals* closure )
 {
     AndUtil* util = (AndUtil*)XP_CALLOC( mpool, sizeof(*util) );
     UtilVtable* vtable = (UtilVtable*)XP_CALLOC( mpool, sizeof(*vtable) );
-    util->env = envp;
-    JNIEnv* env = *envp;
+    util->ti = ti;
+    JNIEnv* env = ENVFORME( util->ti );
     if ( NULL != jutil ) {
         util->jutil = (*env)->NewGlobalRef( env, jutil );
     }
@@ -743,7 +743,7 @@ void
 destroyUtil( XW_UtilCtxt** utilc )
 {
     AndUtil* util = (AndUtil*)*utilc;
-    JNIEnv *env = *util->env;
+    JNIEnv* env = ENVFORME( util->ti );
 
     int ii;
     for ( ii = 0; ii < VSIZE(util->userStrings); ++ii ) {
diff --git a/xwords4/android/XWords4/jni/utilwrapper.h b/xwords4/android/XWords4/jni/utilwrapper.h
index 6c9d3cd23..44a21acc3 100644
--- a/xwords4/android/XWords4/jni/utilwrapper.h
+++ b/xwords4/android/XWords4/jni/utilwrapper.h
@@ -27,7 +27,7 @@
 #include "util.h"
 #include "andglobals.h"
 
-XW_UtilCtxt* makeUtil( MPFORMAL JNIEnv** env, jobject j_util,
+XW_UtilCtxt* makeUtil( MPFORMAL EnvThreadInfo* ti, jobject j_util,
                        CurGameInfo* gi, AndGlobals* globals );
 void destroyUtil( XW_UtilCtxt** util );
 
diff --git a/xwords4/android/XWords4/jni/xportwrapper.c b/xwords4/android/XWords4/jni/xportwrapper.c
index c821245a1..8c984b007 100644
--- a/xwords4/android/XWords4/jni/xportwrapper.c
+++ b/xwords4/android/XWords4/jni/xportwrapper.c
@@ -24,7 +24,7 @@
 
 typedef struct _AndTransportProcs {
     TransportProcs tp;
-    JNIEnv** envp;
+    EnvThreadInfo* ti;
     jobject jxport;
     MPSLOT
 } AndTransportProcs;
@@ -56,7 +56,7 @@ and_xport_getFlags( void* closure )
     jint result = 0;
     AndTransportProcs* aprocs = (AndTransportProcs*)closure;
     if ( NULL != aprocs->jxport ) {
-        JNIEnv* env = *aprocs->envp;
+        JNIEnv* env = ENVFORME( aprocs->ti );
         const char* sig = "()I";
         jmethodID mid = getMethodID( env, aprocs->jxport, "getFlags", sig );
 
@@ -73,7 +73,7 @@ and_xport_send( const XP_U8* buf, XP_U16 len, const CommsAddrRec* addr,
     LOG_FUNC();
     AndTransportProcs* aprocs = (AndTransportProcs*)closure;
     if ( NULL != aprocs->jxport ) {
-        JNIEnv* env = *aprocs->envp;
+        JNIEnv* env = ENVFORME( aprocs->ti );
         const char* sig = "([BL" PKG_PATH("jni/CommsAddrRec") ";I)I";
         jmethodID mid = getMethodID( env, aprocs->jxport, "transportSend", sig );
 
@@ -94,7 +94,7 @@ and_xport_relayStatus( void* closure, CommsRelayState newState )
 {
     AndTransportProcs* aprocs = (AndTransportProcs*)closure;
     if ( NULL != aprocs->jxport ) {
-        JNIEnv* env = *aprocs->envp;
+        JNIEnv* env = ENVFORME( aprocs->ti );
         const char* sig = "(L" PKG_PATH("jni/TransportProcs$CommsRelayState") ";)V";
         jmethodID mid = getMethodID( env, aprocs->jxport, "relayStatus", sig );
 
@@ -111,7 +111,7 @@ and_xport_relayConnd( void* closure, XP_UCHAR* const room, XP_Bool reconnect,
 {
     AndTransportProcs* aprocs = (AndTransportProcs*)closure;
     if ( NULL != aprocs->jxport ) {
-        JNIEnv* env = *aprocs->envp;
+        JNIEnv* env = ENVFORME( aprocs->ti );
         const char* sig = "(Ljava/lang/String;IZI)V";
         jmethodID mid = getMethodID( env, aprocs->jxport, "relayConnd", sig );
 
@@ -129,7 +129,7 @@ and_xport_sendNoConn( const XP_U8* buf, XP_U16 len,
     jboolean result = false;
     AndTransportProcs* aprocs = (AndTransportProcs*)closure;
     if ( NULL != aprocs && NULL != aprocs->jxport ) {
-        JNIEnv* env = *aprocs->envp;
+        JNIEnv* env = ENVFORME( aprocs->ti );
 
         const char* sig = "([BLjava/lang/String;)Z";
         jmethodID mid = getMethodID( env, aprocs->jxport, 
@@ -148,7 +148,7 @@ and_xport_relayError( void* closure, XWREASON relayErr )
 {
     AndTransportProcs* aprocs = (AndTransportProcs*)closure;
     if ( NULL != aprocs->jxport ) {
-        JNIEnv* env = *aprocs->envp;
+        JNIEnv* env = ENVFORME( aprocs->ti );
         jmethodID mid;
         const char* sig = 
             "(L" PKG_PATH("jni/TransportProcs$XWRELAY_ERROR") ";)V";
@@ -163,16 +163,16 @@ and_xport_relayError( void* closure, XWREASON relayErr )
 }
 
 TransportProcs*
-makeXportProcs( MPFORMAL JNIEnv** envp, jobject jxport )
+makeXportProcs( MPFORMAL EnvThreadInfo* ti, jobject jxport )
 {
     AndTransportProcs* aprocs = NULL;
 
-    JNIEnv* env = *envp;
+    JNIEnv* env = ENVFORME( ti );
     aprocs = (AndTransportProcs*)XP_CALLOC( mpool, sizeof(*aprocs) );
     if ( NULL != jxport ) {
         aprocs->jxport = (*env)->NewGlobalRef( env, jxport );
     }
-    aprocs->envp = envp;
+    aprocs->ti = ti;
     MPASSIGN( aprocs->mpool, mpool );
 
 #ifdef COMMS_XPORT_FLAGSPROC
@@ -192,7 +192,7 @@ void
 destroyXportProcs( TransportProcs** xport )
 {
     AndTransportProcs* aprocs = (AndTransportProcs*)*xport;
-    JNIEnv* env = *aprocs->envp;
+    JNIEnv* env = ENVFORME( aprocs->ti );
     if ( NULL != aprocs->jxport ) {
         (*env)->DeleteGlobalRef( env, aprocs->jxport );
     }
diff --git a/xwords4/android/XWords4/jni/xportwrapper.h b/xwords4/android/XWords4/jni/xportwrapper.h
index 626952e14..24cc95f05 100644
--- a/xwords4/android/XWords4/jni/xportwrapper.h
+++ b/xwords4/android/XWords4/jni/xportwrapper.h
@@ -23,9 +23,12 @@
 
 #include <jni.h>
 
+#include "andglobals.h"
+
 #include "comms.h"
 
-TransportProcs* makeXportProcs( MPFORMAL JNIEnv** env, jobject jxport );
+TransportProcs* makeXportProcs( MPFORMAL EnvThreadInfo* ti, jobject jxport );
+
 void destroyXportProcs( TransportProcs** xport );
 
 #endif
diff --git a/xwords4/android/XWords4/jni/xwjni.c b/xwords4/android/XWords4/jni/xwjni.c
index 20841d256..780ace080 100644
--- a/xwords4/android/XWords4/jni/xwjni.c
+++ b/xwords4/android/XWords4/jni/xwjni.c
@@ -19,6 +19,7 @@
  */
 #include <string.h>
 #include <sys/time.h>
+#include <pthread.h>
 
 #include <jni.h>
 #include <android/log.h>
@@ -37,16 +38,97 @@
 #include "xportwrapper.h"
 #include "anddict.h"
 #include "andutils.h"
+#include "andglobals.h"
 #include "jniutlswrapper.h"
 #include "paths.h"
 
+typedef struct _EnvThreadEntry {
+    JNIEnv* env;
+    pthread_t owner;
+} EnvThreadEntry;
+
+#define MAX_ENV_THREADS 10
+
+struct _EnvThreadInfo {
+    pthread_mutex_t mtxThreads;
+    EnvThreadEntry entries[MAX_ENV_THREADS];
+    XP_U16 nMaps;
+};
+
 /* Globals for the whole game */
 typedef struct _JNIGlobalState {
-    JNIEnv* env;
+    EnvThreadInfo ti;
     DictMgrCtxt* dictMgr;
     MPSLOT
 } JNIGlobalState;
 
+static void
+map_init( EnvThreadInfo* ti )
+{
+    pthread_mutex_init( &ti->mtxThreads, NULL );
+}
+
+static void
+map_destroy( EnvThreadInfo* ti )
+{
+    // XP_ASSERT( 0 == ti->nMaps );
+    XP_LOGF( "%s: had %d threads max", __func__, ti->nMaps );
+    pthread_mutex_destroy( &ti->mtxThreads );
+}
+
+static void
+map_thread( EnvThreadInfo* ti, JNIEnv* env, const char* proc )
+{
+    pthread_t self = pthread_self();
+
+    pthread_mutex_lock( &ti->mtxThreads );
+
+    XP_Bool found = false;
+    for ( int ii = 0; !found && ii < ti->nMaps; ++ii ) {
+        EnvThreadEntry* entry = &ti->entries[ii];
+        found = self == entry->owner;
+        if ( found ) {
+            if ( env != entry->env ) {
+                /* this DOES happen!!! */
+                XP_LOGF( "%s: replacing env %p with env %p for thread %x",
+                         __func__, entry->env, env, (int)self );
+                entry->env = env;
+            }
+        }
+    }
+
+    if ( !found ) {
+        EnvThreadEntry* entry = &ti->entries[ti->nMaps++];
+        entry->owner = self;
+        entry->env = env;
+        XP_LOGF( "%s: mapped env %p to thread %x", __func__, env, (int)self );
+        XP_ASSERT( ti->nMaps < MAX_ENV_THREADS );
+    }
+
+    pthread_mutex_unlock( &ti->mtxThreads );
+}
+
+JNIEnv*
+envForMe( EnvThreadInfo* ti, const char* caller )
+{
+    JNIEnv* result = NULL;
+    pthread_t self = pthread_self();
+    pthread_mutex_lock( &ti->mtxThreads );
+    for ( int ii = 0; ii < ti->nMaps; ++ii ) {
+        if ( self == ti->entries[ii].owner ) {
+            result = ti->entries[ii].env;
+            break;
+        }
+    }
+    pthread_mutex_unlock( &ti->mtxThreads );
+    if( !result ) {
+        XP_LOGF( "no env for %s (thread %x in %d entries)", caller, 
+                 (int)self, ti->nMaps );
+        XP_ASSERT(0);
+    }
+    return result;
+}
+
 JNIEXPORT jint JNICALL
 Java_org_eehouse_android_xw4_jni_XwJNI_initGlobals
 ( JNIEnv* env, jclass C )
@@ -55,7 +137,7 @@ Java_org_eehouse_android_xw4_jni_XwJNI_initGlobals
     MemPoolCtx* mpool = mpool_make();
 #endif
     JNIGlobalState* state = (JNIGlobalState*)XP_CALLOC( mpool, sizeof(*state) );
-    state->env = env;
+    map_init( &state->ti );
     state->dictMgr = dmgr_make( MPPARM_NOCOMMA( mpool ) );
     MPASSIGN( state->mpool, mpool );
     LOG_RETURNF( "%p", state );
@@ -69,11 +151,12 @@ Java_org_eehouse_android_xw4_jni_XwJNI_cleanGlobals
     LOG_FUNC();
     if ( 0 != ptr ) {
         JNIGlobalState* state = (JNIGlobalState*)ptr;
-        XP_ASSERT( state->env == env );
+        XP_ASSERT( ENVFORME(&state->ti) == env );
         dmgr_destroy( state->dictMgr );
 #ifdef MEM_DEBUG
         MemPoolCtx* mpool = state->mpool;
 #endif
+        map_destroy( &state->ti );
         XP_FREE( mpool, state );
         mpool_destroy( mpool );
     }
@@ -386,9 +469,10 @@ Java_org_eehouse_android_xw4_jni_XwJNI_dict_1getInfo
 {
     jboolean result = false;
     JNIGlobalState* state = (JNIGlobalState*)jniGlobalPtr;
-    JNIUtilCtxt* jniutil = makeJNIUtil( MPPARM(state->mpool) &env, jniu );
+    JNIUtilCtxt* jniutil = makeJNIUtil( MPPARM(state->mpool) &state->ti, jniu );
     DictionaryCtxt* dict = makeDict( MPPARM(state->mpool) env, state->dictMgr, 
-                                     jniutil, jname, jDictBytes, jpath, NULL, check );
+                                     jniutil, jname, jDictBytes, jpath, 
+                                     NULL, check );
     if ( NULL != dict ) {
         if ( NULL != jinfo ) {
             XP_LangCode code = dict_getLangCode( dict );
@@ -435,9 +519,8 @@ Java_org_eehouse_android_xw4_jni_XwJNI_dict_1getTileValue
     return dict_getTileValue( (DictionaryCtxt*)dictPtr, tile );
 }
 
-typedef struct _JNIState {
+struct _JNIState {
     XWGame game;
-    JNIEnv* env;
     JNIGlobalState* globalJNI;
     AndGlobals globals;
     XP_U16 curSaveCount;
@@ -446,38 +529,22 @@ typedef struct _JNIState {
     const char* envSetterFunc;
 #endif
     MPSLOT
-} JNIState;
-
-#ifdef DEBUG
-# define CHECK_ENV()                                                    \
-    if ( state->env != 0 && state->env != env ) {                       \
-        XP_LOGF( "ERROR: %s trying to set env when %s still has it",    \
-                 __func__, state->envSetterFunc );                      \
-        XP_ASSERT( state->env == 0 || state->env == env );              \
-    }                                                                   \
-    state->envSetterFunc = __func__;                                    \
-
-#else
-# define CHECK_ENV()
-#endif
+};
 
 #define XWJNI_START() {                                 \
     XP_ASSERT( 0 != gamePtr );                          \
     JNIState* state = (JNIState*)gamePtr;               \
     MPSLOT;                                             \
     MPASSIGN( mpool, state->mpool);                     \
-    /* if reentrant must be from same thread */         \
-    CHECK_ENV();                                        \
-    JNIEnv* _oldEnv = state->env;                       \
-    state->env = env;
+    XP_ASSERT( !!state->globalJNI );                    \
+    map_thread( &state->globalJNI->ti, env, __func__ ); \
 
 #define XWJNI_START_GLOBALS()                           \
     XWJNI_START()                                       \
     AndGlobals* globals = &state->globals;              \
 
-#define XWJNI_END()                             \
-    state->env = _oldEnv;                       \
-    }
+#define XWJNI_END()                                   \
+    }                                                 \
 
 JNIEXPORT jint JNICALL
 Java_org_eehouse_android_xw4_jni_XwJNI_initJNI
@@ -493,7 +560,7 @@ Java_org_eehouse_android_xw4_jni_XwJNI_initJNI
     JNIState* state = (JNIState*)XP_CALLOC( mpool, sizeof(*state) );
     state->globalJNI = (JNIGlobalState*)jniGlobalPtr;
     AndGlobals* globals = &state->globals;
-    globals->state = (struct JNIState*)state;
+    globals->state = (JNIState*)state;
     MPASSIGN( state->mpool, mpool );
     globals->vtMgr = make_vtablemgr(MPPARM_NOCOMMA(mpool));
 
@@ -511,17 +578,18 @@ Java_org_eehouse_android_xw4_jni_XwJNI_game_1makeNewGame
   jstring j_lang )
 {
     XWJNI_START_GLOBALS();
+    EnvThreadInfo* ti = &state->globalJNI->ti;
     CurGameInfo* gi = makeGI( MPPARM(mpool) env, j_gi );
     globals->gi = gi;
-    globals->util = makeUtil( MPPARM(mpool) &state->env, j_util, gi, 
+    globals->util = makeUtil( MPPARM(mpool) ti, j_util, gi, 
                               globals );
-    globals->jniutil = makeJNIUtil( MPPARM(mpool) &state->env, jniu );
+    globals->jniutil = makeJNIUtil( MPPARM(mpool) ti, jniu );
     DrawCtx* dctx = NULL;
     if ( !!j_draw ) {
-        dctx = makeDraw( MPPARM(mpool) &state->env, j_draw );
+        dctx = makeDraw( MPPARM(mpool) ti, j_draw );
     }
     globals->dctx = dctx;
-    globals->xportProcs = makeXportProcs( MPPARM(mpool) &state->env, j_procs );
+    globals->xportProcs = makeXportProcs( MPPARM(mpool) ti, j_procs );
     CommonPrefs cp;
     loadCommonPrefs( env, &cp, j_cp );
 
@@ -559,8 +627,6 @@ JNIEXPORT void JNICALL Java_org_eehouse_android_xw4_jni_XwJNI_game_1dispose
 
     destroyGI( MPPARM(mpool) &globals->gi );
 
-    JNIEnv* oldEnv = state->env;
-    state->env = env;
     game_dispose( &state->game );
 
     destroyDraw( &globals->dctx );
@@ -569,7 +635,6 @@ JNIEXPORT void JNICALL Java_org_eehouse_android_xw4_jni_XwJNI_game_1dispose
     destroyJNIUtil( &globals->jniutil );
     vtmgr_destroy( MPPARM(mpool) globals->vtMgr );
 
-    state->env = oldEnv;
     XP_FREE( mpool, state );
     mpool_destroy( mpool );
 } /* game_dispose */
@@ -585,18 +650,18 @@ Java_org_eehouse_android_xw4_jni_XwJNI_game_1makeFromStream
     DictionaryCtxt* dict;
     PlayerDicts dicts;
     XWJNI_START_GLOBALS();
+    EnvThreadInfo* ti = &state->globalJNI->ti;
 
     globals->gi = (CurGameInfo*)XP_CALLOC( mpool, sizeof(*globals->gi) );
-    globals->util = makeUtil( MPPARM(mpool) &state->env, 
-                              jutil, globals->gi, globals );
-    globals->jniutil = makeJNIUtil( MPPARM(mpool) &state->env, jniu );
+    globals->util = makeUtil( MPPARM(mpool) ti, jutil, globals->gi, globals);
+    globals->jniutil = makeJNIUtil( MPPARM(mpool) ti, jniu );
     makeDicts( MPPARM(state->globalJNI->mpool) env, state->globalJNI->dictMgr, 
                globals->jniutil, &dict, &dicts, jdictNames, jdicts, jpaths, 
                jlang );
     if ( !!jdraw ) {
-        globals->dctx = makeDraw( MPPARM(mpool) &state->env, jdraw );
+        globals->dctx = makeDraw( MPPARM(mpool) ti, jdraw );
     }
-    globals->xportProcs = makeXportProcs( MPPARM(mpool) &state->env, jprocs );
+    globals->xportProcs = makeXportProcs( MPPARM(mpool) ti, jprocs );
 
     XWStreamCtxt* stream = streamFromJStream( MPPARM(mpool) env, 
                                               globals->vtMgr, jstream );
@@ -673,7 +738,7 @@ Java_org_eehouse_android_xw4_jni_XwJNI_board_1setDraw
 {
     XWJNI_START_GLOBALS();
 
-    DrawCtx* newDraw = makeDraw( MPPARM(mpool) &state->env, jdraw );
+    DrawCtx* newDraw = makeDraw( MPPARM(mpool) &state->globalJNI->ti, jdraw );
     board_setDraw( state->game.board, newDraw );
 
     destroyDraw( &globals->dctx );
@@ -1664,7 +1729,7 @@ Java_org_eehouse_android_xw4_jni_XwJNI_dict_1iter_1init
     JNIGlobalState* state = (JNIGlobalState*)jniGlobalPtr;
     DictIterData* data = XP_CALLOC( state->mpool, sizeof(*data) );
     data->env = env;
-    JNIUtilCtxt* jniutil = makeJNIUtil( MPPARM(state->mpool) &data->env, jniu );
+    JNIUtilCtxt* jniutil = makeJNIUtil( MPPARM(state->mpool) &state->ti, jniu );
     DictionaryCtxt* dict = makeDict( MPPARM(state->mpool) env, state->dictMgr, 
                                      jniutil, jname, jDictBytes, jpath, NULL, 
                                      false );