Ho anch'io lo stesso "problema", funziona solo con java -cp . nomeclasse

Innanzitutto, è un problema? Cosa comporta il fatto di dover usare -cp?

versione java: 1.7.0_04
su windows XP.

qui sotto trovate la i messaggi che appaiono con java -verbose nomeclasse

Grazie a tutti.

....
[Loaded java.io.OutputStreamWriter from shared objects file]
[Loaded sun.nio.cs.StreamEncoder from shared objects file]
[Loaded java.nio.charset.Charset from shared objects file]
[Loaded java.nio.charset.spi.CharsetProvider from shared objects file]
[Loaded sun.nio.cs.FastCharsetProvider from shared objects file]
[Loaded sun.nio.cs.StandardCharsets from shared objects file]
[Loaded sun.util.PreHashedMap from shared objects file]
[Loaded sun.nio.cs.StandardCharsets$Aliases from shared objects file]
[Loaded sun.nio.cs.StandardCharsets$Classes from shared objects file]
[Loaded sun.nio.cs.StandardCharsets$Cache from shared objects file]
[Loaded sun.security.action.GetPropertyAction from shared objects file]
[Loaded java.util.Arrays from shared objects file]
[Loaded sun.nio.cs.HistoricallyNamedCharset from shared objects file]
[Loaded sun.nio.cs.MS1252 from shared objects file]
[Loaded sun.nio.cs.SingleByte from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.lang.Class$1 from shared objects file]
[Loaded sun.reflect.ReflectionFactory$1 from shared objects file]
[Loaded sun.reflect.NativeConstructorAccessorImpl from shared objects file]
[Loaded sun.reflect.DelegatingConstructorAccessorImpl from shared objects file]
[Loaded sun.nio.cs.ArrayEncoder from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.nio.charset.CharsetEncoder from shared objects file]
[Loaded sun.nio.cs.SingleByte$Encoder from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.nio.charset.CodingErrorAction from shared objects file]
[Loaded java.nio.ByteBuffer from shared objects file]
[Loaded java.nio.HeapByteBuffer from shared objects file]
[Loaded java.nio.Bits from shared objects file]
[Loaded java.nio.ByteOrder from shared objects file]
[Loaded sun.misc.JavaNioAccess from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.nio.Bits$1 from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.io.BufferedWriter from shared objects file]
[Loaded java.io.File from shared objects file]
[Loaded java.io.FileSystem from shared objects file]
[Loaded java.io.Win32FileSystem from shared objects file]
[Loaded java.io.WinNTFileSystem from shared objects file]
[Loaded java.io.ExpiringCache from shared objects file]
[Loaded java.util.LinkedHashMap from shared objects file]
[Loaded java.io.ExpiringCache$1 from shared objects file]
[Loaded java.util.LinkedHashMap$Entry from shared objects file]
[Loaded java.lang.ClassLoader$3 from shared objects file]
[Loaded java.io.ExpiringCache$Entry from shared objects file]
[Loaded java.lang.ClassLoader$NativeLibrary from shared objects file]
[Loaded java.lang.Terminator from shared objects file]
[Loaded sun.misc.SignalHandler from shared objects file]
[Loaded java.lang.Terminator$1 from shared objects file]
[Loaded sun.misc.Signal from shared objects file]
[Loaded sun.misc.NativeSignalHandler from shared objects file]
[Loaded sun.misc.OSEnvironment from shared objects file]
[Loaded sun.io.Win32ErrorMode from shared objects file]
[Loaded sun.misc.JavaLangAccess from shared objects file]
[Loaded java.lang.System$2 from shared objects file]
[Loaded java.lang.NullPointerException from shared objects file]
[Loaded java.lang.ArithmeticException from shared objects file]
[Loaded java.lang.IllegalArgumentException from shared objects file]
[Loaded java.lang.Compiler from shared objects file]
[Loaded java.lang.Compiler$1 from shared objects file]
[Loaded sun.misc.Launcher from shared objects file]
[Loaded java.net.URLStreamHandlerFactory from shared objects file]
[Loaded sun.misc.Launcher$Factory from shared objects file]
[Loaded java.security.SecureClassLoader from shared objects file]
[Loaded java.net.URLClassLoader from shared objects file]
[Loaded sun.misc.Launcher$ExtClassLoader from shared objects file]
[Loaded sun.security.util.Debug from shared objects file]
[Loaded java.lang.ClassLoader$ParallelLoaders from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.WeakHashMap from shared objects file]
[Loaded java.util.WeakHashMap$Entry from shared objects file]
[Loaded java.util.Collections$SetFromMap from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.WeakHashMap$KeySet from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.misc.JavaNetAccess from shared objects file]
[Loaded java.net.URLClassLoader$7 from shared objects file]
[Loaded java.util.StringTokenizer from shared objects file]
[Loaded java.security.PrivilegedExceptionAction from shared objects file]
[Loaded sun.misc.Launcher$ExtClassLoader$1 from shared objects file]
[Loaded sun.misc.MetaIndex from shared objects file]
[Loaded java.lang.Readable from shared objects file]
[Loaded java.io.Reader from shared objects file]
[Loaded java.io.BufferedReader from shared objects file]
[Loaded java.io.InputStreamReader from shared objects file]
[Loaded java.io.FileReader from shared objects file]
[Loaded sun.nio.cs.StreamDecoder from shared objects file]
[Loaded sun.nio.cs.ArrayDecoder from shared objects file]
[Loaded java.nio.charset.CharsetDecoder from shared objects file]
[Loaded sun.nio.cs.SingleByte$Decoder from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.nio.CharBuffer from shared objects file]
[Loaded java.nio.HeapCharBuffer from shared objects file]
[Loaded java.nio.charset.CoderResult from shared objects file]
[Loaded java.nio.charset.CoderResult$Cache from shared objects file]
[Loaded java.nio.charset.CoderResult$1 from shared objects file]
[Loaded java.nio.charset.CoderResult$2 from shared objects file]
[Loaded java.lang.reflect.Array from shared objects file]
[Loaded java.util.Locale from shared objects file]
[Loaded sun.util.locale.LocaleObjectCache from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.Locale$Cache from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.concurrent.ConcurrentMap from shared objects file]
[Loaded java.util.concurrent.ConcurrentHashMap from shared objects file]
[Loaded java.util.concurrent.ConcurrentHashMap$HashEntry from shared objects file]
[Loaded java.util.concurrent.locks.Lock from shared objects file]
[Loaded java.util.concurrent.locks.ReentrantLock from shared objects file]
[Loaded java.util.concurrent.ConcurrentHashMap$Segment from shared objects file]
[Loaded java.util.concurrent.locks.AbstractOwnableSynchron izer from shared objects file]
[Loaded java.util.concurrent.locks.AbstractQueuedSynchroni zer from shared objects file]
[Loaded java.util.concurrent.locks.ReentrantLock$Sync from shared objects file]
[Loaded java.util.concurrent.locks.ReentrantLock$NonfairSy nc from shared objects file]
[Loaded java.util.concurrent.locks.AbstractQueuedSynchroni zer$Node from shared objects file]
[Loaded sun.util.locale.BaseLocale from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.util.locale.BaseLocale$Cache from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.util.locale.BaseLocale$Key from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.util.locale.LocaleObjectCache$CacheEntry from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.Locale$LocaleKey from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.util.locale.LocaleUtils from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.lang.CharacterData from shared objects file]
[Loaded java.lang.CharacterDataLatin1 from shared objects file]
[Loaded sun.net.www.ParseUtil from shared objects file]
[Loaded java.util.BitSet from shared objects file]
[Loaded java.net.URL from shared objects file]
[Loaded java.net.Parts from shared objects file]
[Loaded java.net.URLStreamHandler from shared objects file]
[Loaded sun.net.www.protocol.file.Handler from shared objects file]
[Loaded sun.misc.JavaSecurityAccess from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.security.ProtectionDomain$1 from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.misc.JavaSecurityProtectionDomainAccess from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.security.ProtectionDomain$3 from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.security.CodeSource from shared objects file]
[Loaded java.security.ProtectionDomain$Key from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.security.Principal from shared objects file]
[Loaded java.util.HashSet from shared objects file]
[Loaded sun.misc.URLClassPath from shared objects file]
[Loaded sun.net.www.protocol.jar.Handler from shared objects file]
[Loaded sun.misc.Launcher$AppClassLoader from shared objects file]
[Loaded sun.misc.Launcher$AppClassLoader$1 from shared objects file]
[Loaded java.lang.SystemClassLoaderAction from shared objects file]
[Loaded java.lang.Enum from shared objects file]
[Loaded sun.launcher.LauncherHelper from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.lang.StringCoding from shared objects file]
[Loaded java.lang.ThreadLocal$ThreadLocalMap from shared objects file]
[Loaded java.lang.ThreadLocal$ThreadLocalMap$Entry from shared objects file]
[Loaded java.lang.StringCoding$StringDecoder from shared objects file]
[Loaded java.net.URLClassLoader$1 from shared objects file]
[Loaded sun.net.util.URLUtil from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.misc.URLClassPath$3 from shared objects file]
[Loaded sun.misc.URLClassPath$Loader from shared objects file]
[Loaded sun.misc.URLClassPath$JarLoader from shared objects file]
[Loaded java.security.PrivilegedActionException from shared objects file]
[Loaded sun.misc.URLClassPath$FileLoader from shared objects file]
[Loaded sun.launcher.LauncherHelper$ResourceBundleHolder from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.ResourceBundle from shared objects file]
[Loaded java.util.ResourceBundle$1 from shared objects file]
[Loaded java.util.ResourceBundle$RBClassLoader from shared objects file]
[Loaded java.util.ResourceBundle$RBClassLoader$1 from shared objects file]
[Loaded java.util.ResourceBundle$Control from shared objects file]
[Loaded java.util.Arrays$ArrayList from shared objects file]
[Loaded java.util.ResourceBundle$Control$CandidateListCach e from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.ResourceBundle$CacheKey from shared objects file]
[Loaded java.util.ResourceBundle$CacheKeyReference from shared objects file]
[Loaded java.util.ResourceBundle$LoaderReference from shared objects file]
[Loaded java.util.AbstractSequentialList from shared objects file]
[Loaded java.util.Queue from shared objects file]
[Loaded java.util.Deque from shared objects file]
[Loaded java.util.LinkedList from shared objects file]
[Loaded java.util.LinkedList$Node from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.ListResourceBundle from shared objects file]
[Loaded sun.launcher.resources.launcher from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.ResourceBundle$BundleReference from shared objects file]
[Loaded sun.launcher.resources.launcher_it from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.ResourceBundle$Control$1 from shared objects file]
[Loaded sun.misc.Launcher$BootClassPathHolder from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.misc.Launcher$BootClassPathHolder$1 from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded sun.misc.URLClassPath$JarLoader$1 from shared objects file]
[Loaded sun.misc.FileURLMapper from shared objects file]
[Loaded java.io.IOException from shared objects file]
[Loaded java.io.FileNotFoundException from shared objects file]
[Loaded java.net.URLClassLoader$2 from shared objects file]
[Loaded java.text.Format from shared objects file]
[Loaded java.text.MessageFormat from shared objects file]
[Loaded java.util.Locale$Category from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.util.Locale$1 from C:\Programmi\Java\jre7\lib\rt.jar]
[Loaded java.text.FieldPosition from shared objects file]
[Loaded java.util.Date from shared objects file]
[Loaded java.text.AttributedCharacterIterator$Attribute from shared objects file]
[Loaded java.text.Format$Field from shared objects file]
[Loaded java.text.MessageFormat$Field from shared objects file]
Errore: impossibile trovare o caricare la classe principale Helloworld
[Loaded java.lang.Shutdown from shared objects file]
[Loaded java.lang.Shutdown$Lock from shared objects file]