diff --git a/contracts/src/main/kotlin/com/r3corda/contracts/CommercialPaper.kt b/contracts/src/main/kotlin/com/r3corda/contracts/CommercialPaper.kt
index d14689fd7f..139f7db55c 100644
--- a/contracts/src/main/kotlin/com/r3corda/contracts/CommercialPaper.kt
+++ b/contracts/src/main/kotlin/com/r3corda/contracts/CommercialPaper.kt
@@ -81,12 +81,11 @@ class CommercialPaper : Contract {
         val command = tx.commands.requireSingleCommand<CommercialPaper.Commands>()
         // If it's an issue, we can't take notary from inputs, so it must be specified in the command
         val cmdVal = command.value
-        val timestamp: TimestampCommand? = if (cmdVal is Commands.Issue)
-            tx.getTimestampBy(cmdVal.notary)
-        else if (cmdVal is Commands.Redeem)
-            tx.getTimestampBy(cmdVal.notary)
-        else
-            null
+        val timestamp: TimestampCommand? = when (cmdVal) {
+            is Commands.Issue -> tx.getTimestampBy(cmdVal.notary)
+            is Commands.Redeem -> tx.getTimestampBy(cmdVal.notary)
+            else -> null
+        }
 
         for ((inputs, outputs, key) in groups) {
             when (command.value) {
diff --git a/core/src/main/kotlin/com/r3corda/core/crypto/CryptoUtilities.kt b/core/src/main/kotlin/com/r3corda/core/crypto/CryptoUtilities.kt
index fc6169e5a0..45b545153e 100644
--- a/core/src/main/kotlin/com/r3corda/core/crypto/CryptoUtilities.kt
+++ b/core/src/main/kotlin/com/r3corda/core/crypto/CryptoUtilities.kt
@@ -19,7 +19,7 @@ fun newSecureRandom(): SecureRandom {
 }
 
 // "sealed" here means there can't be any subclasses other than the ones defined here.
-sealed class SecureHash constructor(bits: ByteArray) : OpaqueBytes(bits) {
+sealed class SecureHash(bits: ByteArray) : OpaqueBytes(bits) {
     class SHA256(bits: ByteArray) : SecureHash(bits) {
         init {
             require(bits.size == 32)
diff --git a/core/src/main/kotlin/com/r3corda/protocols/FetchDataProtocol.kt b/core/src/main/kotlin/com/r3corda/protocols/FetchDataProtocol.kt
index f2269ae491..25d50ae6a9 100644
--- a/core/src/main/kotlin/com/r3corda/protocols/FetchDataProtocol.kt
+++ b/core/src/main/kotlin/com/r3corda/protocols/FetchDataProtocol.kt
@@ -7,8 +7,6 @@ import com.r3corda.core.crypto.SecureHash
 import com.r3corda.core.protocols.ProtocolLogic
 import com.r3corda.core.random63BitValue
 import com.r3corda.core.utilities.UntrustworthyData
-import com.r3corda.protocols.FetchDataProtocol.DownloadedVsRequestedDataMismatch
-import com.r3corda.protocols.FetchDataProtocol.HashNotFound
 import java.util.*
 
 /**
diff --git a/core/src/main/kotlin/com/r3corda/protocols/RatesFixProtocol.kt b/core/src/main/kotlin/com/r3corda/protocols/RatesFixProtocol.kt
index 048f1a8767..d61ad3d968 100644
--- a/core/src/main/kotlin/com/r3corda/protocols/RatesFixProtocol.kt
+++ b/core/src/main/kotlin/com/r3corda/protocols/RatesFixProtocol.kt
@@ -11,7 +11,6 @@ import com.r3corda.core.protocols.ProtocolLogic
 import com.r3corda.core.random63BitValue
 import com.r3corda.core.utilities.ProgressTracker
 import com.r3corda.core.utilities.suggestInterestRateAnnouncementTimeWindow
-import com.r3corda.protocols.RatesFixProtocol.FixOutOfRange
 import java.math.BigDecimal
 import java.time.Duration
 import java.time.Instant
diff --git a/core/src/main/kotlin/protocols/AbstractStateReplacementProtocol.kt b/core/src/main/kotlin/protocols/AbstractStateReplacementProtocol.kt
index a2a52e2d80..02b9f9ae4d 100644
--- a/core/src/main/kotlin/protocols/AbstractStateReplacementProtocol.kt
+++ b/core/src/main/kotlin/protocols/AbstractStateReplacementProtocol.kt
@@ -13,8 +13,6 @@ import com.r3corda.core.utilities.ProgressTracker
 import com.r3corda.protocols.NotaryProtocol
 import com.r3corda.protocols.PartyRequestMessage
 import com.r3corda.protocols.ResolveTransactionsProtocol
-import protocols.AbstractStateReplacementProtocol.Acceptor
-import protocols.AbstractStateReplacementProtocol.Instigator
 import java.security.PublicKey
 
 /**
diff --git a/core/src/main/kotlin/protocols/NotaryChangeProtocol.kt b/core/src/main/kotlin/protocols/NotaryChangeProtocol.kt
index b0f6d13456..7ec371acc4 100644
--- a/core/src/main/kotlin/protocols/NotaryChangeProtocol.kt
+++ b/core/src/main/kotlin/protocols/NotaryChangeProtocol.kt
@@ -4,8 +4,6 @@ import co.paralleluniverse.fibers.Suspendable
 import com.r3corda.core.contracts.*
 import com.r3corda.core.crypto.Party
 import com.r3corda.core.utilities.ProgressTracker
-import protocols.NotaryChangeProtocol.Acceptor
-import protocols.NotaryChangeProtocol.Instigator
 import java.security.PublicKey
 
 /**
diff --git a/node/src/main/kotlin/com/r3corda/node/services/network/InMemoryMessagingNetwork.kt b/node/src/main/kotlin/com/r3corda/node/services/network/InMemoryMessagingNetwork.kt
index 864b898e6c..65f22209f9 100644
--- a/node/src/main/kotlin/com/r3corda/node/services/network/InMemoryMessagingNetwork.kt
+++ b/node/src/main/kotlin/com/r3corda/node/services/network/InMemoryMessagingNetwork.kt
@@ -10,7 +10,6 @@ import com.r3corda.core.messaging.*
 import com.r3corda.core.serialization.SingletonSerializeAsToken
 import com.r3corda.core.utilities.loggerFor
 import com.r3corda.core.utilities.trace
-import com.r3corda.node.services.network.InMemoryMessagingNetwork.InMemoryMessaging
 import org.slf4j.LoggerFactory
 import rx.Observable
 import rx.subjects.PublishSubject
diff --git a/node/src/main/kotlin/com/r3corda/node/utilities/ANSIProgressRenderer.kt b/node/src/main/kotlin/com/r3corda/node/utilities/ANSIProgressRenderer.kt
index 0ee7077e75..e9bcf5bf99 100644
--- a/node/src/main/kotlin/com/r3corda/node/utilities/ANSIProgressRenderer.kt
+++ b/node/src/main/kotlin/com/r3corda/node/utilities/ANSIProgressRenderer.kt
@@ -3,7 +3,6 @@ package com.r3corda.node.utilities
 import com.r3corda.core.utilities.BriefLogFormatter
 import com.r3corda.core.utilities.Emoji
 import com.r3corda.core.utilities.ProgressTracker
-import com.r3corda.node.utilities.ANSIProgressRenderer.progressTracker
 import org.fusesource.jansi.Ansi
 import org.fusesource.jansi.AnsiConsole
 import org.fusesource.jansi.AnsiOutputStream