Create rule S6555: Null pointers should not be dereferenced (#1703)

rules/S6555/java/metadata.json

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+{
+  "title": "Null pointers should not be dereferenced",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "10min"
+  },
+  "tags": [
+    "cwe",
+    "cert",
+    "symbolic-execution"
+  ],
+  "extra": {
+    "replacementRules": [
+
+    ],
+    "legacyKeys": [
+
+    ]
+  },
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-6555",
+  "sqKey": "S6555",
+  "scope": "Main",
+  "securityStandards": {
+    "CERT": [
+      "EXP34-C.",
+      "EXP01-J."
+    ],
+    "CWE": [
+      476
+    ]
+  },
+  "defaultQualityProfiles": [],
+  "quickfix": "unknown"
+}

rules/S6555/java/rule.adoc

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+== Why is this an issue?
+
+A reference to ``++null++`` should never be dereferenced/accessed. Doing so will cause a ``++NullPointerException++`` to be thrown. At best, such an exception will cause abrupt program termination. At worst, it could expose debugging information that would be useful to an attacker, or it could allow an attacker to bypass security measures.
+
+
+
+=== Noncompliant code example
+
+[source,java]
+----
+@CheckForNull
+String getName() {
+  boolean condition = getCondition();
+  return condition ? "name" : null;
+}
+
+public boolean isNameEmpty() {
+  return getName().length() == 0; // Noncompliant; the result of getName() could be null, but isn't null-checked
+}
+----
+
+[source,java]
+----
+void paint(Color color) {
+  if (color == null) {
+    System.out.println("Unable to apply color " + color.toString());  // Noncompliant; NullPointerException will be thrown
+    return;
+  }
+  ...
+}
+----
+
+== Resources
+
+* https://cwe.mitre.org/data/definitions/476[MITRE, CWE-476] - NULL Pointer Dereference
+* https://wiki.sei.cmu.edu/confluence/x/QdcxBQ[CERT, EXP34-C.] - Do not dereference null pointers
+* https://wiki.sei.cmu.edu/confluence/x/aDdGBQ[CERT, EXP01-J.] - Do not use a null in a case where an object is required
+
+ifdef::env-github,rspecator-view[]
+
+'''
+== Implementation Specification
+(visible only on this page)
+
+=== Message
+
+* Fix this access on a value that can be null
+
+'''
+endif::env-github,rspecator-view[]

rules/S6555/metadata.json

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+{
+}