Replace trivial usages of SysProperties.CHECK2 with assertions

h2/src/main/org/h2/engine/Session.java

@@ -722,12 +722,7 @@ public class Session extends SessionWithState implements TransactionStore.Rollba
     }
 
     private void removeTemporaryLobs(boolean onTimeout) {
-        if (SysProperties.CHECK2) {
-            if (this == getDatabase().getLobSession()
-                    && !Thread.holdsLock(this) && !Thread.holdsLock(getDatabase())) {
-                throw DbException.throwInternalError();
-            }
-        }
+        assert this != getDatabase().getLobSession() || Thread.holdsLock(this) || Thread.holdsLock(getDatabase());
         if (temporaryLobs != null) {
             for (Value v : temporaryLobs) {
                 if (!v.isLinkedToTable()) {

h2/src/main/org/h2/index/PageDataLeaf.java

@@ -491,11 +491,7 @@ public class PageDataLeaf extends PageData {
         }
         data.writeByte((byte) type);
         data.writeShortInt(0);
-        if (SysProperties.CHECK2) {
-            if (data.length() != START_PARENT) {
-                DbException.throwInternalError();
-            }
-        }
+        assert data.length() == START_PARENT;
         data.writeInt(parentPageId);
         data.writeVarInt(index.getId());
         data.writeVarInt(columnCount);

h2/src/main/org/h2/index/PageDataNode.java

@@ -351,11 +351,7 @@ public class PageDataNode extends PageData {
         data.reset();
         data.writeByte((byte) Page.TYPE_DATA_NODE);
         data.writeShortInt(0);
-        if (SysProperties.CHECK2) {
-            if (data.length() != START_PARENT) {
-                DbException.throwInternalError();
-            }
-        }
+        assert data.length() == START_PARENT;
         data.writeInt(parentPageId);
         data.writeVarInt(index.getId());
         data.writeInt(rowCountStored);

h2/src/main/org/h2/store/Data.java

@@ -705,13 +705,8 @@ public class Data {
             }
             DbException.throwInternalError("type=" + v.getType());
         }
-        if (SysProperties.CHECK2) {
-            if (pos - start != getValueLen(v, handler)) {
-                throw DbException.throwInternalError(
-                            "value size error: got " + (pos - start) +
-                            " expected " + getValueLen(v, handler));
-            }
-        }
+        assert pos - start == getValueLen(v, handler)
+                : "value size error: got " + (pos - start) + " expected " + getValueLen(v, handler);
     }
 
     /**

h2/src/main/org/h2/store/LobStorageBackend.java

@@ -249,11 +249,7 @@ public class LobStorageBackend implements LobStorageInterface {
      * @return the prepared statement
      */
     PreparedStatement prepare(String sql) throws SQLException {
-        if (SysProperties.CHECK2) {
-            if (!Thread.holdsLock(database)) {
-                throw DbException.throwInternalError();
-            }
-        }
+        assert Thread.holdsLock(database);
         PreparedStatement prep = prepared.remove(sql);
         if (prep == null) {
             prep = conn.prepareStatement(sql);
@@ -268,11 +264,7 @@ public class LobStorageBackend implements LobStorageInterface {
      * @param prep the prepared statement
      */
     void reuse(String sql, PreparedStatement prep) {
-        if (SysProperties.CHECK2) {
-            if (!Thread.holdsLock(database)) {
-                throw DbException.throwInternalError();
-            }
-        }
+        assert Thread.holdsLock(database);
         prepared.put(sql, prep);
     }