diff --git a/tests/common/java/android/net/KeepalivePacketDataTest.kt b/tests/common/java/android/net/KeepalivePacketDataTest.kt
index f464ec6..92ffc5c 100644
--- a/tests/common/java/android/net/KeepalivePacketDataTest.kt
+++ b/tests/common/java/android/net/KeepalivePacketDataTest.kt
@@ -50,9 +50,9 @@
 
     // Add for test because constructor of KeepalivePacketData is protected.
     private inner class TestKeepalivePacketData(
-        srcAddress: InetAddress? = TEST_SRC_ADDRV4,
+        srcAddress: InetAddress = TEST_SRC_ADDRV4,
         srcPort: Int = TEST_SRC_PORT,
-        dstAddress: InetAddress? = TEST_DST_ADDRV4,
+        dstAddress: InetAddress = TEST_DST_ADDRV4,
         dstPort: Int = TEST_DST_PORT,
         data: ByteArray = TESTBYTES
     ) : KeepalivePacketData(srcAddress, srcPort, dstAddress, dstPort, data)
@@ -63,20 +63,6 @@
         var data: TestKeepalivePacketData
 
         try {
-            data = TestKeepalivePacketData(srcAddress = null)
-            fail("Null src address should cause exception")
-        } catch (e: InvalidPacketException) {
-            assertEquals(e.error, ERROR_INVALID_IP_ADDRESS)
-        }
-
-        try {
-            data = TestKeepalivePacketData(dstAddress = null)
-            fail("Null dst address should cause exception")
-        } catch (e: InvalidPacketException) {
-            assertEquals(e.error, ERROR_INVALID_IP_ADDRESS)
-        }
-
-        try {
             data = TestKeepalivePacketData(dstAddress = TEST_ADDRV6)
             fail("Ip family mismatched should cause exception")
         } catch (e: InvalidPacketException) {
@@ -117,4 +103,4 @@
     @Test
     @IgnoreUpTo(Build.VERSION_CODES.Q)
     fun testPacket() = assertTrue(Arrays.equals(TESTBYTES, TestKeepalivePacketData().packet))
-}
\ No newline at end of file
+}
diff --git a/tests/common/java/android/net/NetworkProviderTest.kt b/tests/common/java/android/net/NetworkProviderTest.kt
index fcbb0dd..c6a7346 100644
--- a/tests/common/java/android/net/NetworkProviderTest.kt
+++ b/tests/common/java/android/net/NetworkProviderTest.kt
@@ -67,7 +67,7 @@
 class NetworkProviderTest {
     @Rule @JvmField
     val mIgnoreRule = DevSdkIgnoreRule()
-    private val mCm = context.getSystemService(ConnectivityManager::class.java)
+    private val mCm = context.getSystemService(ConnectivityManager::class.java)!!
     private val mHandlerThread = HandlerThread("${javaClass.simpleName} handler thread")
 
     @Before
diff --git a/tests/cts/net/src/android/net/cts/CaptivePortalTest.kt b/tests/cts/net/src/android/net/cts/CaptivePortalTest.kt
index 1d79806..99222dd 100644
--- a/tests/cts/net/src/android/net/cts/CaptivePortalTest.kt
+++ b/tests/cts/net/src/android/net/cts/CaptivePortalTest.kt
@@ -95,7 +95,7 @@
 @RunWith(AndroidJUnit4::class)
 class CaptivePortalTest {
     private val context: android.content.Context by lazy { getInstrumentation().context }
-    private val cm by lazy { context.getSystemService(ConnectivityManager::class.java) }
+    private val cm by lazy { context.getSystemService(ConnectivityManager::class.java)!! }
     private val pm by lazy { context.packageManager }
     private val utils by lazy { CtsNetUtils(context) }
 
diff --git a/tests/cts/net/src/android/net/cts/DscpPolicyTest.kt b/tests/cts/net/src/android/net/cts/DscpPolicyTest.kt
index db13c49..f73134a 100644
--- a/tests/cts/net/src/android/net/cts/DscpPolicyTest.kt
+++ b/tests/cts/net/src/android/net/cts/DscpPolicyTest.kt
@@ -125,7 +125,7 @@
     private val TEST_TARGET_MAC_ADDR = MacAddress.fromString("12:34:56:78:9a:bc")
 
     private val realContext = InstrumentationRegistry.getContext()
-    private val cm = realContext.getSystemService(ConnectivityManager::class.java)
+    private val cm = realContext.getSystemService(ConnectivityManager::class.java)!!
 
     private val agentsToCleanUp = mutableListOf<NetworkAgent>()
     private val callbacksToCleanUp = mutableListOf<TestableNetworkCallback>()
@@ -160,7 +160,7 @@
         assumeTrue(kernelIsAtLeast(5, 15))
 
         runAsShell(MANAGE_TEST_NETWORKS) {
-            val tnm = realContext.getSystemService(TestNetworkManager::class.java)
+            val tnm = realContext.getSystemService(TestNetworkManager::class.java)!!
 
             // Only statically configure the IPv4 address; for IPv6, use the SLAAC generated
             // address.
@@ -306,7 +306,7 @@
 
         val socket = Os.socket(if (sendV6) AF_INET6 else AF_INET, SOCK_DGRAM or SOCK_NONBLOCK,
                 IPPROTO_UDP)
-        agent.network.bindSocket(socket)
+        checkNotNull(agent.network).bindSocket(socket)
 
         val originalPacket = testPacket.readAsArray()
         Os.sendto(socket, originalPacket, 0 /* bytesOffset */, originalPacket.size, 0 /* flags */,
diff --git a/tests/cts/net/src/android/net/cts/EthernetManagerTest.kt b/tests/cts/net/src/android/net/cts/EthernetManagerTest.kt
index 76a955b..7fe9299 100644
--- a/tests/cts/net/src/android/net/cts/EthernetManagerTest.kt
+++ b/tests/cts/net/src/android/net/cts/EthernetManagerTest.kt
@@ -135,8 +135,8 @@
 class EthernetManagerTest {
 
     private val context by lazy { InstrumentationRegistry.getInstrumentation().context }
-    private val em by lazy { context.getSystemService(EthernetManager::class.java) }
-    private val cm by lazy { context.getSystemService(ConnectivityManager::class.java) }
+    private val em by lazy { context.getSystemService(EthernetManager::class.java)!! }
+    private val cm by lazy { context.getSystemService(ConnectivityManager::class.java)!! }
     private val handler by lazy { Handler(Looper.getMainLooper()) }
 
     private val ifaceListener = EthernetStateListener()
@@ -160,7 +160,7 @@
 
         init {
             tnm = runAsShell(MANAGE_TEST_NETWORKS) {
-                context.getSystemService(TestNetworkManager::class.java)
+                context.getSystemService(TestNetworkManager::class.java)!!
             }
             tapInterface = runAsShell(MANAGE_TEST_NETWORKS) {
                 // Configuring a tun/tap interface always enables the carrier. If hasCarrier is
diff --git a/tests/cts/net/src/android/net/cts/NetworkAgentTest.kt b/tests/cts/net/src/android/net/cts/NetworkAgentTest.kt
index 98ea224..5937655 100644
--- a/tests/cts/net/src/android/net/cts/NetworkAgentTest.kt
+++ b/tests/cts/net/src/android/net/cts/NetworkAgentTest.kt
@@ -257,7 +257,7 @@
         callback: TestableNetworkCallback,
         handler: Handler
     ) {
-        mCM!!.registerBestMatchingNetworkCallback(request, callback, handler)
+        mCM.registerBestMatchingNetworkCallback(request, callback, handler)
         callbacksToCleanUp.add(callback)
     }
 
@@ -394,8 +394,8 @@
                 .setLegacyExtraInfo(legacyExtraInfo).build()
         val (agent, callback) = createConnectedNetworkAgent(initialConfig = config)
         val networkInfo = mCM.getNetworkInfo(agent.network)
-        assertEquals(subtypeLTE, networkInfo.getSubtype())
-        assertEquals(subtypeNameLTE, networkInfo.getSubtypeName())
+        assertEquals(subtypeLTE, networkInfo?.getSubtype())
+        assertEquals(subtypeNameLTE, networkInfo?.getSubtypeName())
         assertEquals(legacyExtraInfo, config.getLegacyExtraInfo())
     }
 
@@ -417,8 +417,8 @@
             val nc = NetworkCapabilities(agent.nc)
             nc.addCapability(NET_CAPABILITY_NOT_METERED)
             agent.sendNetworkCapabilities(nc)
-            callback.expectCaps(agent.network) { it.hasCapability(NET_CAPABILITY_NOT_METERED) }
-            val networkInfo = mCM.getNetworkInfo(agent.network)
+            callback.expectCaps(agent.network!!) { it.hasCapability(NET_CAPABILITY_NOT_METERED) }
+            val networkInfo = mCM.getNetworkInfo(agent.network!!)!!
             assertEquals(subtypeUMTS, networkInfo.getSubtype())
             assertEquals(subtypeNameUMTS, networkInfo.getSubtypeName())
     }
@@ -631,6 +631,7 @@
         val defaultNetwork = mCM.activeNetwork
         assertNotNull(defaultNetwork)
         val defaultNetworkCapabilities = mCM.getNetworkCapabilities(defaultNetwork)
+        assertNotNull(defaultNetworkCapabilities)
         val defaultNetworkTransports = defaultNetworkCapabilities.transportTypes
 
         val agent = createNetworkAgent(initialNc = nc)
@@ -671,7 +672,7 @@
         // This is not very accurate because the test does not control the capabilities of the
         // underlying networks, and because not congested, not roaming, and not suspended are the
         // default anyway. It's still useful as an extra check though.
-        vpnNc = mCM.getNetworkCapabilities(agent.network!!)
+        vpnNc = mCM.getNetworkCapabilities(agent.network!!)!!
         for (cap in listOf(NET_CAPABILITY_NOT_CONGESTED,
                 NET_CAPABILITY_NOT_ROAMING,
                 NET_CAPABILITY_NOT_SUSPENDED)) {
@@ -1041,8 +1042,8 @@
     }
 
     fun QosSocketInfo(agent: NetworkAgent, socket: Closeable) = when (socket) {
-        is Socket -> QosSocketInfo(agent.network, socket)
-        is DatagramSocket -> QosSocketInfo(agent.network, socket)
+        is Socket -> QosSocketInfo(checkNotNull(agent.network), socket)
+        is DatagramSocket -> QosSocketInfo(checkNotNull(agent.network), socket)
         else -> fail("unexpected socket type")
     }
 
@@ -1405,8 +1406,8 @@
         val nc = makeTestNetworkCapabilities(ifName, transports).also {
             if (transports.contains(TRANSPORT_VPN)) {
                 val sessionId = "NetworkAgentTest-${Process.myPid()}"
-                it.transportInfo = VpnTransportInfo(VpnManager.TYPE_VPN_PLATFORM, sessionId,
-                    /*bypassable=*/ false, /*longLivedTcpConnectionsExpensive=*/ false)
+                it.setTransportInfo(VpnTransportInfo(VpnManager.TYPE_VPN_PLATFORM, sessionId,
+                    /*bypassable=*/ false, /*longLivedTcpConnectionsExpensive=*/ false))
                 it.underlyingNetworks = listOf()
             }
         }
diff --git a/tests/cts/net/src/android/net/cts/NetworkInfoTest.kt b/tests/cts/net/src/android/net/cts/NetworkInfoTest.kt
index d6120f8..d8ec761 100644
--- a/tests/cts/net/src/android/net/cts/NetworkInfoTest.kt
+++ b/tests/cts/net/src/android/net/cts/NetworkInfoTest.kt
@@ -104,13 +104,6 @@
             NetworkInfo(ConnectivityManager.MAX_NETWORK_TYPE + 1,
                     TelephonyManager.NETWORK_TYPE_LTE, MOBILE_TYPE_NAME, LTE_SUBTYPE_NAME)
         }
-
-        if (SdkLevel.isAtLeastT()) {
-            assertFailsWith<NullPointerException> { NetworkInfo(null) }
-        } else {
-            // Doesn't immediately crash on S-
-            NetworkInfo(null)
-        }
     }
 
     @Test
@@ -133,21 +126,11 @@
         constructor.isAccessible = true
         val incorrectDetailedState = constructor.newInstance("any", 200) as DetailedState
         if (SdkLevel.isAtLeastT()) {
-            assertFailsWith<NullPointerException> {
-                NetworkInfo(null)
-            }
-            assertFailsWith<NullPointerException> {
-                networkInfo.setDetailedState(null, "reason", "extraInfo")
-            }
             // This actually throws ArrayOutOfBoundsException because of the implementation of
             // EnumMap, but that's an implementation detail so accept any crash.
             assertFails {
                 networkInfo.setDetailedState(incorrectDetailedState, "reason", "extraInfo")
             }
-        } else {
-            // Doesn't immediately crash on S-
-            NetworkInfo(null)
-            networkInfo.setDetailedState(null, "reason", "extraInfo")
         }
     }
-}
\ No newline at end of file
+}
diff --git a/tests/cts/net/src/android/net/cts/NetworkScoreTest.kt b/tests/cts/net/src/android/net/cts/NetworkScoreTest.kt
index 2704dd3..e660b1e 100644
--- a/tests/cts/net/src/android/net/cts/NetworkScoreTest.kt
+++ b/tests/cts/net/src/android/net/cts/NetworkScoreTest.kt
@@ -67,7 +67,7 @@
 @RunWith(DevSdkIgnoreRunner::class)
 class NetworkScoreTest {
     private val TAG = javaClass.simpleName
-    private val mCm = testContext.getSystemService(ConnectivityManager::class.java)
+    private val mCm = testContext.getSystemService(ConnectivityManager::class.java)!!
     private val mHandlerThread = HandlerThread("$TAG handler thread")
     private val mHandler by lazy { Handler(mHandlerThread.looper) }
     private val agentsToCleanUp = Collections.synchronizedList(mutableListOf<NetworkAgent>())
@@ -111,7 +111,7 @@
     // made for ConnectivityServiceTest.
     // TODO : have TestNetworkCallback work for NetworkAgent too and remove this class.
     private class AgentWrapper(val agent: NetworkAgent) : HasNetwork {
-        override val network = agent.network
+        override val network = checkNotNull(agent.network)
         fun sendNetworkScore(s: NetworkScore) = agent.sendNetworkScore(s)
     }
 
diff --git a/tests/cts/net/src/android/net/cts/NsdManagerTest.kt b/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
index 7be4f78..49a6ef1 100644
--- a/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
+++ b/tests/cts/net/src/android/net/cts/NsdManagerTest.kt
@@ -159,9 +159,9 @@
     val ignoreRule = DevSdkIgnoreRule()
 
     private val context by lazy { InstrumentationRegistry.getInstrumentation().context }
-    private val nsdManager by lazy { context.getSystemService(NsdManager::class.java) }
+    private val nsdManager by lazy { context.getSystemService(NsdManager::class.java)!! }
 
-    private val cm by lazy { context.getSystemService(ConnectivityManager::class.java) }
+    private val cm by lazy { context.getSystemService(ConnectivityManager::class.java)!! }
     private val serviceName = "NsdTest%09d".format(Random().nextInt(1_000_000_000))
     private val serviceType = "_nmt%09d._tcp".format(Random().nextInt(1_000_000_000))
     private val handlerThread = HandlerThread(NsdManagerTest::class.java.simpleName)
@@ -397,7 +397,7 @@
     }
 
     private fun createTestNetwork(): TestTapNetwork {
-        val tnm = context.getSystemService(TestNetworkManager::class.java)
+        val tnm = context.getSystemService(TestNetworkManager::class.java)!!
         val iface = tnm.createTapInterface()
         val cb = TestableNetworkCallback()
         val testNetworkSpecifier = TestNetworkSpecifier(iface.interfaceName)
diff --git a/tests/cts/net/src/android/net/cts/ProxyTest.kt b/tests/cts/net/src/android/net/cts/ProxyTest.kt
index a661b26..872dbb9 100644
--- a/tests/cts/net/src/android/net/cts/ProxyTest.kt
+++ b/tests/cts/net/src/android/net/cts/ProxyTest.kt
@@ -70,7 +70,7 @@
 
     private fun getDefaultProxy(): ProxyInfo? {
         return InstrumentationRegistry.getInstrumentation().context
-                .getSystemService(ConnectivityManager::class.java)
+                .getSystemService(ConnectivityManager::class.java)!!
                 .getDefaultProxy()
     }
 
@@ -100,4 +100,4 @@
             Proxy.setHttpProxyConfiguration(original)
         }
     }
-}
\ No newline at end of file
+}
diff --git a/tests/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt b/tests/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt
index 67e1296..e264b55 100644
--- a/tests/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt
+++ b/tests/integration/src/com/android/server/net/integrationtests/ConnectivityServiceIntegrationTest.kt
@@ -56,6 +56,7 @@
 import com.android.testutils.RecorderCallback.CallbackEntry.LinkPropertiesChanged
 import com.android.testutils.TestableNetworkCallback
 import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
 import kotlin.test.fail
 import org.junit.After
@@ -291,6 +292,7 @@
         val capportData = testCb.expect<LinkPropertiesChanged>(na, TEST_TIMEOUT_MS) {
             it.lp.captivePortalData != null
         }.lp.captivePortalData
+        assertNotNull(capportData)
         assertTrue(capportData.isCaptive)
         assertEquals(Uri.parse("https://login.capport.android.com"), capportData.userPortalUrl)
         assertEquals(Uri.parse("https://venueinfo.capport.android.com"), capportData.venueInfoUrl)
diff --git a/tests/integration/src/com/android/server/net/integrationtests/HttpResponse.kt b/tests/integration/src/com/android/server/net/integrationtests/HttpResponse.kt
index e206313..467708a 100644
--- a/tests/integration/src/com/android/server/net/integrationtests/HttpResponse.kt
+++ b/tests/integration/src/com/android/server/net/integrationtests/HttpResponse.kt
@@ -20,9 +20,9 @@
 import android.os.Parcelable
 
 data class HttpResponse(
-    val requestUrl: String,
+    val requestUrl: String?,
     val responseCode: Int,
-    val content: String = "",
+    val content: String? = "",
     val redirectUrl: String? = null
 ) : Parcelable {
     constructor(p: Parcel): this(p.readString(), p.readInt(), p.readString(), p.readString())
@@ -46,4 +46,4 @@
         override fun createFromParcel(source: Parcel) = HttpResponse(source)
         override fun newArray(size: Int) = arrayOfNulls<HttpResponse?>(size)
     }
-}
\ No newline at end of file
+}
diff --git a/tests/integration/src/com/android/server/net/integrationtests/NetworkStackInstrumentationService.kt b/tests/integration/src/com/android/server/net/integrationtests/NetworkStackInstrumentationService.kt
index e807952..104d063 100644
--- a/tests/integration/src/com/android/server/net/integrationtests/NetworkStackInstrumentationService.kt
+++ b/tests/integration/src/com/android/server/net/integrationtests/NetworkStackInstrumentationService.kt
@@ -70,7 +70,7 @@
          * request is seen, the test will fail.
          */
         override fun addHttpResponse(response: HttpResponse) {
-            httpResponses.getValue(response.requestUrl).add(response)
+            httpResponses.getValue(checkNotNull(response.requestUrl)).add(response)
         }
 
         /**
@@ -81,4 +81,4 @@
             return ArrayList(httpRequestUrls)
         }
     }
-}
\ No newline at end of file
+}
diff --git a/tests/integration/src/com/android/server/net/integrationtests/TestNetworkStackService.kt b/tests/integration/src/com/android/server/net/integrationtests/TestNetworkStackService.kt
index 361c968..7e227c4 100644
--- a/tests/integration/src/com/android/server/net/integrationtests/TestNetworkStackService.kt
+++ b/tests/integration/src/com/android/server/net/integrationtests/TestNetworkStackService.kt
@@ -69,7 +69,8 @@
         url: URL,
         private val response: HttpResponse
     ) : HttpURLConnection(url) {
-        private val responseBytes = response.content.toByteArray(StandardCharsets.UTF_8)
+        private val responseBytes = checkNotNull(response.content)
+            .toByteArray(StandardCharsets.UTF_8)
         override fun getResponseCode() = response.responseCode
         override fun getContentLengthLong() = responseBytes.size.toLong()
         override fun getHeaderField(field: String): String? {
diff --git a/tests/unit/java/android/net/NetworkTemplateTest.kt b/tests/unit/java/android/net/NetworkTemplateTest.kt
index 2f6c76b..f0da89f 100644
--- a/tests/unit/java/android/net/NetworkTemplateTest.kt
+++ b/tests/unit/java/android/net/NetworkTemplateTest.kt
@@ -218,18 +218,6 @@
         templateNullWifiKey.assertDoesNotMatch(identWifiNullKey)
     }
 
-    @DevSdkIgnoreRule.IgnoreAfter(Build.VERSION_CODES.TIRAMISU)
-    @Test
-    fun testBuildTemplateMobileAll_nullSubscriberId() {
-        val templateMobileAllWithNullImsi = buildTemplateMobileAll(null)
-        val setWithNull = HashSet<String?>().apply {
-            add(null)
-        }
-        val templateFromBuilder = NetworkTemplate.Builder(MATCH_MOBILE).setMeteredness(METERED_YES)
-            .setSubscriberIds(setWithNull).build()
-        assertEquals(templateFromBuilder, templateMobileAllWithNullImsi)
-    }
-
     @Test
     fun testMobileMatches() {
         val templateMobileImsi1 = buildTemplateMobileAll(TEST_IMSI1)
diff --git a/tests/unit/java/com/android/server/connectivity/FullScoreTest.kt b/tests/unit/java/com/android/server/connectivity/FullScoreTest.kt
index 3520c5b..0a3822a 100644
--- a/tests/unit/java/com/android/server/connectivity/FullScoreTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/FullScoreTest.kt
@@ -74,7 +74,7 @@
 
     private val TAG = this::class.simpleName
 
-    private var wtfHandler: Log.TerribleFailureHandler? = null
+    private lateinit var wtfHandler: Log.TerribleFailureHandler
 
     @Before
     fun setUp() {
diff --git a/tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt b/tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt
index f88da1f..b667e5f 100644
--- a/tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt
+++ b/tests/unit/java/com/android/server/connectivity/mdns/MdnsPacketTest.kt
@@ -59,12 +59,12 @@
         }
 
         assertEquals(InetAddresses.parseNumericAddress("192.0.2.123"),
-                (packet.authorityRecords[0] as MdnsInetAddressRecord).inet4Address)
+                (packet.authorityRecords[0] as MdnsInetAddressRecord).inet4Address!!)
         assertEquals(InetAddresses.parseNumericAddress("2001:db8::123"),
-                (packet.authorityRecords[1] as MdnsInetAddressRecord).inet6Address)
+                (packet.authorityRecords[1] as MdnsInetAddressRecord).inet6Address!!)
         assertEquals(InetAddresses.parseNumericAddress("2001:db8::456"),
-                (packet.authorityRecords[2] as MdnsInetAddressRecord).inet6Address)
+                (packet.authorityRecords[2] as MdnsInetAddressRecord).inet6Address!!)
         assertEquals(InetAddresses.parseNumericAddress("2001:db8::789"),
-                (packet.authorityRecords[3] as MdnsInetAddressRecord).inet6Address)
+                (packet.authorityRecords[3] as MdnsInetAddressRecord).inet6Address!!)
     }
 }